The science end of it is clear enough: our species appeared several hundred thousand years ago in Africa, one of several hominid species of that period, including our ancestral branch Homo erectus, the first of our genus to venture outside Africa.

If reincarnation were a general feature of life, stories of it would be occurring cross-culturally.

Are there certain holidays that Atheists avoid due to their religious connections?

Though I doubt reincarnation occurs, the idea that this could be part of the natural universe is independent from whether or not any god(s) are operating behind or through it.

Not only does it not require "faith" to be an atheist, that aspect should play no role whatsoever in being an atheist

In a philosophical sense atheism is at ground a rejection of supernatural entities as informative principles