The only difference between Krsna, Radharani, Balarama and Visnu/Narayana, is Kṛṣṇa is the first, the original Supreme Personality of Godhead and cause of all causes.

Visnu-tattva expansions of Krsna have 93.75% of Krsna's qualities which means they have 60 of Krsna's 64 qualities.

Krsna has 100% of His own qualities because He has all 64 qualities in full.

The only difference between Visnu,  Balarama, Radharani and Krsna, is Krsna is the first, the original Supreme Personality of Godhead and cause of all causes.

Krsna has 4 extra qualities than His Visnu-tattva expansions who have 60 of Krsna's 64 qualities, 9 more than Siva-tattva (Lord Siva) and 14 more than jiva-tattva (jiva-souls)

The percentage of Krsna's 64 qualities is mathematically worked out here so we can see what His various expansions have based on the acquired qualities they exhibit.

Visnu/Narayana forms that includes Balarama, Maha-Visnu, Garbhodakashayi Visnu etc (Visnu-tattva) manifest from Krsna's first expansion Balarama.

Krsna is the original Personality of Godhead, His first expansion is Balarama, who then expands as the original catur vyuha or quadruple expansions.

1) Vasudeva 

2) Sankarsasna

3) Pradyumna 

4) Aniruddha

These original catur vyuha expansions reside in Mathura and Dvaraka. 

From them twenty four forms of Visnu expand. They are named differently according to the arrangement of the conch, disc, lotus and club in Their hands. 

All of these twenty four forms reside in each Vaikuntha planet with the predominating Deity of that planet. 

From the original catur vyuha the second catur vyuha expands. 

In this second catur vyuha the form of Sankarsana is also called Maha Sankarsana. 

From Kṛṣṇa’s first expansion Balarāma, eventually comes Maha-Sankarsana, who then expands as Maha-Visnu who creates the material worlds.

Maha Sankarsana expands as the three purusa-avataras-

 

1 - Maha-Visnu also known as Karanodakasayi-Visnu, 

2 - Garbhodakasayi-Visnu also known as Hiraņyagarbha 

3 - Ksirodakasayi-Visnu also known as Paramatma and Supersoul. 

This is confirmed in the Satvata-tantra:

visnos tu trini rupani

purusakhyany atho viduh

ekam tu mahatah srastr

dvitiyam tv anda-samsthitam

trtiyam sarva-bhuta-stham

tani jnatva vimucyate

"For material creation, Lord Krsna's plenary expansion assumes three Visnus. 

The first, Maha-Visnu, creates the total material energy, known as mahat-tattva. 

The second, Garbhodakasayi Visnu, enters into all the universes to create diversities in each of them. 

The third, Ksirodakasayi Visnu, is diffused as the all-pervading Supersoul in all the universes and is known as Paramatma. 

He is present even within the atoms. Anyone who knows these three Visnus can be liberated from material entanglement." (Satvata-tantra quoted in BG, Ch 7 text 4 purport)

Not even Balarama has 64 qualities all the time but can manifest them under Krsna's will, He has 60 of Krsna's 64 qualities which is 93.75% as explained in above.

Furthermore Siva-tattva or Lord Siva has 85.938% of Krsna's qualities and the jiva-tattva's (jiva-souls or marginal living entities) that includes Lord Brahma and Nārada muni have 78.125% of Krsna's qualities.

There are basically only two types of living entities, Visnu-tattva (God) and jiva-tattva (individual jiva-souls)

Srila Prabhupada – “In the Padma Purana, it is said there are two kinds of spiritual entities; one is called the jiva-tattva, and the other is called the Visnu-tattva." (87th Chapter, Krsna Book, Prayers by the Personified Vedas)

Srila Prabhupada - "The "immediate" expansions of the Lord are called svāṁśa or personal direct expansions (Visnu-tattva who are Krsna playing another role in His own pastimes). The "separated" expansions of the Lord are called vibhinnāṁśa - (jiva-tattva or independent jiva-souls) like us." (BG, Ch 10 text 37, Purport)

Srila Prabhupada - We are marginal (the jiva-souls) who are sometimes internal, sometimes external. When we are under the internal energy, that is our normal life, and when we are under the external energy, that is our abnormal life. Therefore, we are called marginal energy; we can be either this way or that way. But being qualitatively one with the purusa, our tendency is to remain in the internal energy. Being in the external energy is our artificial attempt." (Letter to Lilavati, Allston, Mass 25 April, 1969)

Lord Siva has 85.938% of Krsna's qualities and has 55 of Krsna's 64 qualities. Lord Siva is in a unique league of his own.

All other sakti-tattvas in the Visnu-tattva category come under the heading of Kṛṣṇa's permanent internal energy meaning they can never fall down to the material creation. They are technically called Visnu-"sakti"-tattva.

The jiva-soul's (marginal living entities) have 78.125% of Krsna's 64 qualities which is having 50 of  Krsna's qualities.

Krsna is the only one who has all 64 of His own qualities in full (100%) at all times.

The only difference between Krsna, who has 64 qualities and Visnu, who has 60 of Krsna's 64 qualities, is the 4 extra qualities Krsna always has in full that is sometimes only partially exhibited by Visnu /Narayana /Balarama expansions.

Radharani is in a special league of Her own created by Krsna and non-different from Krsna. Srimati Radharani and Krsna are exactly the same but exist as two.

She was created so Krsna can experience loving exchanges, affection and a two-sided relationship with a women. Radharani is the highest expression and personification of Krsna's energy (sakti)

Krsna divided Himself into "two" just so He could experience loving exchanges with a women. 

As said above, when Krsna wanted to experience loving emotions, affection and exchanges, He knew such love could never happen with just "one", or Him alone, so He created Srimati Radharani. Krsna divided Himself into "two" just so He could experience those loving exchanges.

Srila Prabhupada - "When Krsna wants to be attracted by a woman, He has to create such a woman from His own energy. That woman is Rādhārāṇī. It is explained by the Gosvāmīs that Rādhārāṇī is the manifestation of the pleasure potency of the Supreme Personality of Godhead. When the Supreme Lord wants to derive transcendental pleasure, He has to create a woman from His internal potency and that women is Srimati Radharani." (SB, Canto 3 Ch 31 text 38, Purport)

Srila Prabhupada - "Rādhā and Kṛṣṇa are one and the same, but They have assumed two bodies. Thus They enjoy each other, tasting the mellows of love. The two transcendentalists Rādhā and Kṛṣṇa are a puzzle to materialists. 

The description of Rādhā and Kṛṣṇa from the diary of Śrīla Svarūpa Dāmodara Gosvāmī is a condensed explanation, but one needs great spiritual insight to understand the mystery of these two personalities. One is enjoying as two. 

Śrī Kṛṣṇa is the potent factor, and Śrīmatī Rādhārāṇī is the internal potency. According to Vedānta philosophy, there is no difference between the potent and the potency; they are identical. We cannot differentiate between one and the other, any more than we can separate fire from heat. Everything in the Absolute is inconceivable in relative existence. 

Therefore in relative cognizance it is very difficult to assimilate this truth of the oneness between the potent and the potency. The philosophy of inconceivable oneness and difference propounded by Lord Caitanya is the only source of understanding for such intricacies of transcendence. In fact, Rādhārāṇī is the internal potency of Śrī Kṛṣṇa, and She eternally intensifies the pleasure of Śrī Kṛṣṇa. Impersonalists cannot understand this without the help of a mahā-bhāgavata devotee.

The very name “Rādhā” suggests that Śrīmatī Rādhārāṇī is eternally the topmost mistress of the comforts of Śrī Kṛṣṇa. As such, She is the medium transmitting the living entities’ service to Śrī Kṛṣṇa. Devotees in Vṛndāvana therefore seek the mercy of Śrīmatī Rādhārāṇī in order to be recognized as loving servitors of Śrī Kṛṣṇa." (CC Adi 4.56, Translation and Purport)

The only difference between Radharani and Krsna is Krsna is the first. 

Lets understand the meaning of Krsna's sakti (energy)

Srila Prabhupada - "Kṛṣṇa expands Himself into various viṣṇu-tattva forms, and Śrīmatī Rādhārāṇī expands Herself into various śakti-tattva forms, by Her internal potency, as multiforms of the goddess of fortune." (Krsna Book 52)

"Sakti" refers to Radharani and Her expansions but also has other meanings too. Sakti also refers to all the energies of Kṛṣṇa, they are all His sakti just like the sunshine rays coming from the Sun-disc. 

Radharani has those qualities too but not always like Krsna does. Still, Radha and Krsna are identical.

1 - Krsna is the Supreme Personality of Godhead and cause of all causes and always has 64 qualities in full.

2 -Visnu-tattva (Visnu/Narayana) has 60 qualities which is 93.75% of Krsna's 64 qualities.

3 - Siva-tattva (Lord Siva) has 55 qualities which is 85.938% of Krsna's 64 qualities. 

4 - Jiva-tattva (individual jiva-souls) has 50 qualities which is 78.125% of Krsna's 64 qualities.  

Lord Siva is between Visnu-tattva (God) and jiva-tattva (jiva-souls). 

The Supreme Personality of Godhead Lord Krsna has all the 64 transcendental qualities in full.

Furthermore, the extent of Krsna's following qualities are inconceivable.

(1) Beautiful features of the entire body

(2) Marked with all auspicious characteristics

(3) Extremely pleasing

(4) Effulgent

(5) Strong

(6) Ever youthful

(7) Wonderful linguist

(8) Truthful

(9) Talks pleasingly

(10) Fluent

(11) Highly learned

(12) Highly intelligent

(13) Genius

(14) Artistic

(15) Extremely clever

(16) Expert

(17) Grateful

(18) Firmly determined

(19) An expert judge of time and circumstances

(20) Sees and speaks on the authority of Vedas, or scriptures

(21) Pure

(22) Self-controlled

(23) Steadfast

(24) Forbearing

(25) Forgiving

(26) Grave

(27) Self-satisfied

(28) Possessing equilibrium

(29) Magnanimous

(30) Religious

(31) Heroic

(32) Compassionate

(33) Respectful

(34) Gentle

(35) Liberal

(36) Shy

(37) The protector of surrendered souls

(38) Happy

(39) The well-wisher of devotees

(40) Controlled by love

(41) all-auspicious

(42) Most powerful

(43) all-famous

(44) Popular

(45) Partial to devotees

(46) Very attractive to all women

(47) all-worship able

(48) all-opulent

(49) all-honourable

(50) The supreme controller.

(51) Changeless

(52) all-cognizant

(53) Ever fresh

(54) sat-cit-ananda-vigraha which means eternity-knowledge-bliss-form, an eternal blissful spiritual bodily form.

(55) Possessing all mystic perfections.

(56) He has inconceivable potency.

(57) Uncountable universes generate from His body.

(58) He is the original source of all incarnations.

(59) He is the giver of salvation to the enemies whom He kills.

(60) He is the attractor of liberated souls.

Besides these sixty transcendental qualities, Krsna has four more, which are not manifested even in the Visnu/Narayana form of Godhead, what to speak of the demigods or living entities. They are as follows:

(61) He is the performer of wonderful varieties of pastimes (especially His childhood pastimes).

(62) He is surrounded by devotees endowed with wonderful love of Godhead.

(63) He can attract all living entities all over the universes by playing on His flute.

(64) He has a wonderful excellence of beauty which cannot be rivaled anywhere in the creation.

The Absolute Truth is anandamaya (desiring to increase His joy), hence from His original form He expands and becomes many. 

These emanations from the Supreme Person Krsna are of two categories: full expansions known as Visnu-tattva, and partially manifested expansions known as jiva-tattva or the jiva-souls.

The Lord's various full and partial expansions and the Lord Himself simultaneously co-exist, only appearing to manifest under the influence of time.

These expansions of the Supreme Person are known as Visnu-tattva, and they are also Supreme Absolute Truth. 

While non-different from the Lord, the Visnu-tattvas all accept their own role as Godhead in the mood of Servitor to the "original" Supreme Being.

This relationship is the foundation of Vedic monotheism, which encompasses the inconceivable, absolute personal nature of the original Godhead.

The Supreme Being possesses two other expansive qualities known as Siva-tattva and jiva-tattva. 

Together with Visnu-tattva, these three qualities are representative of the Absolute Person's internal, external and marginal energies.

The Lord has expanded Himself as unlimited Visnu/Narayana Forms, Lord Siva, Lord Brahma and the individual jiva-souls, all are Krsna's expansions each with different potency.

Krsna is called Param Purushottam, Purnavatar or Supreme Personality of Godhead and cause of all causes.

Srila Prabhupada - "Learned scholars in transcendental subjects have carefully analyzed the summum bonum Krsna to have sixty-four principal attributes. All the expansions or categories of the Lord possess only some percentages of these qualities. But Sri Krsna is the possessor of the qualities cent percent.

And His personal expansions such as svayam-prakasa, tad-ekatma up to the categories of the avataras who are all visnu-tattva expansions possess up to 93.75% of these transcendental qualities.

Lord Siva, who is neither avatara nor avesa nor in between them, possesses 85.938% of Krsna's 64 qualities.

The jiva-souls or the individual marginal living entities in different possess up to the limit of 78.125% of  Krsna's 64 qualities.

In the conditioned state of material existence, the marginal living entity (jiva-soul) possesses Krsna's qualities  in very minute quantity, varying in terms of the pious life of the individual marginal living entity (jiva-soul).

The most perfect of marginal living entities (jiva-souls) is Lord Brahma, the supreme administrator of each material universe, He possesses 78.125% of Krsna's 64 qualities.

All other demigods have the same attributes in less quantity, whereas human beings possess the attributes in very minute quantity.

The standard of perfection for a human being is to develop the qualities up to 78.125% which is having 50 of Krsna's 64 qualities. 

The eternal individual jiva-souls can never possess attributes like Siva, Visnu or Krsna.

An individual jiva-soul can become godly by developing the 78.125% of Krsna's transcendental qualities, but can never become a demigod like Siva, or God Visnu or Krsna. All individual jīva-souls can become Brahma in the material in due course of time but never Visnu or Siva as explained above.

The godly living beings who are all residents of the planets in the spiritual sky are eternal associates of God in different spiritual planets called Hari-dhama and Mahesa-dhama. The abode of Lord Krsna above all spiritual planets is called Krsnaloka or Goloka Vrndavana, and the perfected marginal living entities (jiva-souls), by developing 78.125% of  Krsna's 64 qualities can enter the planet of Krsnaloka after leaving the present material body." (SB, Canto 1 Ch 3 Text 29)

Radharani is the highest ultimate personification of Krsna's sakti-tattva.

Everything comes from Krsna but Krsna needs no one. So in this sense, He is everything and no one exists outside of Him. Consequently, when Krsna wants to enjoy, He expands the potency or energy within Himself that gives him enjoyment. 

This potency is a person Krsna expands too. Her name is Srimati Radharani. She is an expansion of Krsna but is the maintainer of all sakti-tattva internal expansions. But everything originated from Krsna.

Radharani is not a different person from Krsna, or, rather, she is both one with and different from Him. How could two people be one person or one person be two? A simple example will illustrate how this is so. The sun cannot exist without the sunshine, nor the sunshine without the sun.

We say, "the sun is in my room"—even though the sun itself is ninety-three million miles away—because the sun appears in the form of its energy.

Therefore the energy (the sunshine) and the energetic (the sun) are simultaneously one and different.

Similarly, Radha and Krsna are simultaneously one and different.

Krsna, the self-effulgent Lord, is the Supreme Personality of Godhead, and Srimati Radharani is His supreme pleasure energy. Together They constitute the complete Absolute Truth.

One cannot understand anything about Radha and Krsna through mental speculation. Krsna and His potencies are achintya,inconceivable, and ananta, unlimited. He is the very source of the mind itself, and therefore He is beyond the mind.

The limited mind cannot understand the unlimited Personality of Godhead.

The Vedic literature explains this very logically: "that which is transcendental to material nature is inconceivable, whereas speculative arguments are all mundane.

Since mundane arguments cannot touch transcendental subject matters, one should not try to understand transcendental subjects through mundane arguments. When ordinary mundane intellectuals try to explain or interpret the identity or pastimes of Radha and Krsna.

Krsna's unlimited nature bewilders them, and therefore they misconstrue everything. Thus they sometimes consider Radha and Krsna to be like an ordinary boy and girl of the material world. But although they often pose as scholars, they do not know what they are talking about. One should therefore strictly avoid the confused mundane ideas of such blundering intellectuals. If one wishes to understand Radha and Krsna, one must understand Them by hearing submissively from a bona fide authority

The original authority on Krsna is Krsna Himself. Everyone is first an authority regarding his own self, and this is also true regarding Krsna.

Moreover, since Krsna is unlimited, no one else can understand Him fully. Krsna's disciple Arjuna confirms this as follows in Bhagavad-gita:

svayam evatmanatmanam
vettha tvam purusottama
bhuta-bhavana bhutesa
deva-deva jagat pate

"Indeed, You alone know Yourself by Your own potencies, O origin of all, Lord of all beings, God of gods, O Supreme Person, Lord of the universe!" (BG, Ch 10 text 15).^÷^.