Nibbana, Khandas, reincarnation, cessation, non-returners, and the Buddha

So I have a question. In Buddhism there have been, at later times moreso, been raised ideas about the return of the Buddha, Bodhisattvas, Arhats, and other followers of the Buddha after the said Nibbana or cessation from the Saha World.

It would dictate that in the Ancient days of the Vedas when a Bhagavan would descend into this World, they would Descend in an “Avatar” and perform sacred duties. Each Avatar would be considered an Eternal Emanation of Parabrahman (God). However, the same Bhagavan could Avatar multiple times, each time it being a separate Avatar, as a unique plenary portion.

This brings me to the Buddhist Perspective. In Buddhism things jump from Theravada to Mahayana. In Theravada there are once returners, twice returners, and non returners, Arhats, and the Buddha.

In Mahayana there is a strong sense of reincarnation of Buddhas, Bodhisattvas, and others both because of altruism and Samsara.

Yet we would all have to agree that Samsara’s grip ends at liberation.

Does non-returner, Buddha, Arhat, at least, mean that there is nothing left to be reborn, therefore the individual is freed forever from this world at the end of their life upon the burning up of the Khandas? Yet they could Emanate back into this world, with Empty Khandas again, being an “Emanation” of the previous Spiritual Being, ready for the next experience of life?