Marduk

“This then assumes the first half of Genesis is post 6th century B.C. work”

Not necessarily, as I said before Abraham was from Ur in Sumer, where these stories originated in 2500 BCE or earlier, they may well have been a shared oral tradition that was ‘monotheified’ later. People of many nations passed through Palestine for eons, sharing stories etc. it was a big trade route.

FunkyRes

That most certainly is possible, I have no problems with that- but coming from Babylon itself I find unlikely, at least coming from Babylon late enough to be a result of the captivity is unlikely.