All living entities (Visnu-tattva, Visnu-sakti-tattva and jiva-tattva [jiva-souls]) are expansions of the Original Living Entity, Krsna.

Srila Prabhupada - "Regarding your question about Krsna's associates, the principle is that all living entities are expansions of the "Original Living Entity, Krsna" but there are different grades of living entities- 

1 - Visnu-tattva (Krsna's direct expansions who are nondifferent from Krsna or God. Visnu-tattva is almost equal to the level of the Personality of Godhead. 

2 - Jiva-tattva (individual jiva-souls who have their own independent personality separate from Krsna's Personality. And Jiva-tattva (the jiva-souls) are His minute separated particles. 

Srila Prabhupada - "When Lord Caitanya appeared, Nityananda Prabhu and Advaita Prabhu were Visnu-tattva; whereas Gadadhara Prabhu and Srivas Prabhu were Visnu-"sakti"-tattva." (London 8 Dec, 1969)

All of Krsna's energy are His "sakti expansions.

1 - Some sakti personalities are direct Visnu expansions of Krsna like Balarama, Ramachandra, Narsingadeva, Narayana, Maha-Visnu,  Garbhodakashayi Visnu 

2 - Other sakti expansions are Krsna's more intimate associates like Srimati Radharani and the gopis of Vrindavana are known as Krsna's internal "Visnu-"sakti"-tattva" energy. 

3 - Other forms of "sakti" are Krsna's separated individual jiva-jiva-souls (jiva-tattva)

4 - And Krsna's material energy is also His "sakti" energies.

In other words, everything is Krsna's sakti energy and comes from Krsna because He is the Supreme Personality of Godhead and cause of all causes.  

Srila Prabhupāda -  "Gadadhara is the incarnation of devotional energy and of the internal potency who is sakti-tattva, the confidential worshipper of the Visnu-tattva. In this incarnation, Radharani was able to spend time with Her Lord as an intimate associate who helped spread the pastimes and glories of Sri Caitanya Mahaprabhu." (CC.Adi 10.15 purport)

Jiva-tattva or jiva-soul is also sakti-tattva because all of Krsna's energy is His sakti expansion. However, there are in different categories of sakti-tattva, some under Visnu-tattva, while others under jiva-tattva (jiva-soul) and also means matter too.

Srila Prabhupāda - "Srivasa Thakura is the incarnation of the pure devotee of the Lord. He is jiva-tattva, the leader of all pure unalloyed devotees. All glories to Lord Caitanya Mahaprabhu and Lord Nityananda! All glories to Advaita Prabhu, and all glories to the devotees of Lord Caitanya, headed by Srivasa!" (C.C.Adi 10.2)

Srimati Radharani is the internal sakti energy, we are marginal sakti energy (jiva-souls)

Srila Prabhupada - "Regarding your question about our relationship with Srimati Radharani, She is the internal energy, we are marginal energy (jiva-souls). Marginal means 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 (jiva-souls); 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 - 25 April, 1969)

Srila Prabhupāda - "Lord Nityananda IS Balarama Himself, not an expansion of Him. Srila Narottama das Thakura has sung that the Lord who appeared as the Son of Nanda Maharaja has now appeared as the son of Sacidevi; and the same Balarama has appeared as Nityananda. This is the statement of Srila Narottama das Thakura." (Letter to Jayagovinda dasa, London 8 Dec, 1969)

Srila Prabhupada - "The pleasure potency of Śrī Kṛṣṇa formerly known as Vṛndāvaneśvarī is now personified in the form of Śrī Gadādhara Paṇḍita in the pastimes of Lord Caitanya Mahāprabhu. Śrī Svarūpa Dāmodara Gosvāmī has pointed out that in the shape of Lakṣmī, the pleasure potency of Kṛṣṇa, she was formerly very dear to the Lord as Śyāmasundara vallabhā. 

The same Śyāmasundara vallabhā is now present as Gadādhara Paṇḍita. Formerly, as Lalitā-sakhī, she was always devoted to Śrīmatī Rādhārāṇī. Gadadhara Goswami is a representative of a perfect brahmana spiritual master He is the Pleasure Potency of Sri Krsna (Srimati Radharani) He is a learned scholar and Gadadhara Pandit is simultaneously an incarnation of Srimati Radharani and Lalita-sakhi. 

Gadadhara is the incarnation of devotional energy and of the internal potency who is sakti-tattva, the confidential worshipper of the Visnu-tattva. In this incarnation, Radharani was able to spend time with Her Lord as an intimate associate who helped spread the pastimes and glories of Sri Caitanya Mahaprabhu." (CC.Adi 10.15 purport)

Caitanya Caritamrta - "These two captains, with Their soldiers, such as Srivasa Thakura, travel everywhere, chanting the holy name of the Lord." (CC.Adi 3.75)

Caitanya Caritamrta - "The devotees headed by Srivasa are His smaller limbs. They are like His hands, face and eyes and His disc and other weapons." (CC.Adi 6.38)

Caitanya Caritamrta - "Srivasa, Haridasa, Ramadasa, Gadadhara, Murari, Mukunda, Candrasekhara and Vakresvara are all glorious and are all learned scholars, but the sentiment of servitude to Lord Caitanya makes them mad in ecstasy." (CC.Adi 6.49-50)

Caitanya Caritamrta - "The Lord’s marginal energy (jiva-soul) is Srivas Thakur. There are innumerable pure devotees of the Lord, headed by Srivasa Thakura, who are known as unalloyed devotees." (CC.Adi 7.16)

Caitanya Caritamrta - "Even cats and dogs in the household of Srivasa Thakura were liberated. Cats and dogs and other animals are not expected to become devotees, but, in the association of a pure devotee, they are also delivered. The entire family of Srivasa was made up of exalted spiritual personalities. In the Gaura-ganodesa dipika (90), Srivasa Pandita is described as an incarnation of Narada Muni, and Sri Rama Pandita, his younger brother, is said to be an incarnation of Parvata Muni, a great friend of Narada’s. 

Śrīvāsa Paṇḍita’s wife, Mālinī, is celebrated as an incarnation of the nurse Ambikā, who fed Lord Kṛṣṇa with her breast milk, and his niece Nārāyaṇī, the mother of Ṭhākura Vṛndāvana dāsa, the author of Śrī Caitanya-bhāgavata, was the sister of Ambikā in kṛṣṇa-līlā. We also understand from the description of Śrī Caitanya-bhāgavata that after Lord Caitanya Mahāprabhu’s acceptance of the sannyāsa order, Śrīvāsa Paṇḍita left Navadvīpa, possibly because of feelings of separation, and domiciled at Kumārahaṭṭa." (CC.Adi 10.8)

God (Visnu-tattva) and the individual jiva-souls (jiva-tattva) are together even in every atom in the material creation. God (Visnu or Narayana) and the jiva-tattvas (the individual jiva-souls) are within every atom. Therefore within the heart of all living entities and within the atom, God is known as Kshirodakashayi Visnu. 

In Gauḍīya Vaisnavism there are three different forms, or aspects, of Visnu as-

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

2 - Garbhodakasayi-Visnu also known as Hiraņyagarbha 

3 - Ksirodakasayi-Visnu also known as Paramatma and Super Soul. 

They all enter and manage different aspects of the material creation.

Kṣīrodakaśāyī-Viṣṇu resides in the heart of every living creature as a four hand expansion similar to that of Mahā-Viṣṇu. 

He is also referred to as Paramātmā or super-soul. His abode is the Vaikuṇṭha. 

His personal abode is Kshirasagara (Milk Ocean) and He is realised as Aniruddha expansion of Nārāyaņa.

Visnu/Narayana are expansions of Krsna the Supreme Personality of Godhead and cause of all causes.

Tamala Krsna - "Srila Prabhupada, someone asked a question the other day about the atom which I couldn’t give the answer to. His question is that if we say that within the atom the living entity, the jiva, is present, and life symptoms means six symptoms of birth, growth"

Srila Prabhupada - "That’s all right. Their life symptoms has not yet come. But there is."

Jayadvaita - "Potential."

Srila Prabhupada - "Yes."

Tamala Krsna - "His question was… It was sort of a dual question. At what time, or what…? Just like at the time of disintegration of this body, the living entity leaves this body and the body disintegrates, so does the atomic body also disintegrate when the living entity leaves it and moves to a higher body?"

Srila Prabhupada - "Atomic body? Atomic body means material body. Unless you are free from this material body, the atomic body will go on with you. That means unless you are mukta, the atomic body will go on. Mind, intelligence, ego — they are also atomic, finer atomic body."

Tamala Krsna - "But within each atom the living entity is present?"

Srila Prabhupada - "Yes, God is present; therefore living entity is present."

Tamala Krsna -"So the living entity is present within the atom just as I am present within this body. When I leave this body, my body breaks apart."

Srila Prabhupada - "Yes, you leave this body, enter another body."

Tamala Krsna -"Right."

Srila Prabhupada - "By nature’s law."

Tamala Krsna -"And when I leave this body, the body breaks apart."

Srila Prabhupada - "Eh?"

Tamala Krsna - "When I leave this body, the body dis…"

Srila Prabhupada - "The body is already atomic combination."

Tamala Krsna "Yes."

Srila Prabhupada - "So it remains atomic combination, you leave the body."

Tamala Krsna -"Yes, it remains…"

Srila Prabhupada - "You leave the house. That does not mean the house is finished."

Tamala Krsna - "Right, I can understand that."

Hamsaduta - "He’s asking that if the soul leaves the atomic particle, then does the particle break apart. Isn’t it?"

Srila Prabhupada - "No, no. You have not left atomic particle."

Tamala Krsna - "No, but you, you’re… I think you were saying that within the atom there’s also a living entity. So when that living entity leaves the atomic particle does the particle break apart? Or doesn’t it? I mean what…?"

Srila Prabhupada - "Just try to understand. From the sastra, you understand that andantara-stham: “God lives within the atom."

Tamala Krsna - "Yes."

Srila Prabhupada - "And when the God is there, living entity’s also there. This… This much you try to understand. Because God and living entity, they remain together, as two friends. God is trying to save this fallen friend. That is the information from Upanisad. So when God is there, the living entity is also there."

Rupanuga - "So Paramatma and jivatma are always together."

Srila Prabhupada - "Yes."

Pancadravida - "The jivas inside the atom, are they like impersonalists who are in the Brahman?"

Srila Prabhupada - "That you consider. He has not developed his consciousness, practically, it is like dead." (Morning Walk April 4 1975, Mayapur).*^^*.