@neil I don't think the writer(s) of Genesis 2:4-6 would have intended or assumed that readers of the narrative would understand its potential relationship to Plato's works. There are clearly missing pieces to the story. You acknowledge this.
If we assume Gmirkin's thesis is correct, what you are postulating is that Genesis is produced directly from
Timaeus and that any details that appear to be missing from the biblical narrative are to be inferred from Plato's work.
I'm proposing that some longer work was derived from
Timaeus first, and that the biblical narrative is a redacted version of the longer narrative, with Genesis 5 inserted into a narrative that spanned from Genesis 2:4-6:4. I would think that the longer narrative would more thoroughly cover the sons of God and account for the creation of the nations of the earth, with Yahweh being the son of God who creates the people of Israel, while other sons of God create the people of other nations.
From Enoch:
(I) Asael taught men to make swords of iron and breast-plates of bronze
and every weapon for war; and he showed them the metals of the earth. how
to work gold, to fashion [adornments] and about silver. to make bracelets
for women; and he instructed them about antimony, and eye-shadow, and
all manner of precious stones and about dyes and varieties ofadornmenrs; and
the children of men fashioned them for themselves and for their
daughters and transgressed; (2) and there arose much impiety on the
earth and they committed fornication and went astray and corrupted their
ways_ (3) Semhazah taught spell-binding and the cutting of roots; Hermoni
taught the loosing of spells, magic, sorcery and sophistry. Baraqel taught the
auguries of the lightning; Kokabiel taught the auguries of the stars; Zikiel
taught the auguries of fire-balls; Arteqif taught the auguries of earth; Simsel
taught the auguries of the sun; Sahrel taught the auguries of the moon. And
they all began to reveal secrets to their wives. (4) Then the giants began to
devour the flesh of men, and mankind began to become few upon the earth;
and as men perished from the earth, their voice went up to heaven: 'Bring our
cause before the Most High, and our destruction before the glory of the Great
One'.
This certainly reads more like Greek mythology. Here the sons of God have been reinterpreted as angels, but I can easily see this being part of the original story, in which these are terrestrial gods like Yahweh-Elohim of Genesis 2-3.
From the LXX:
Gen 3:
4 And the snake said to the woman, "You will not die by death, for God knew that on the day you eat of it your eyes would be opened, and you would be like gods, knowing good and evil."
"Die by death"? What did this really say? Did this really say that she would not be killed by Mot (i.e. another god) or something of that nature?
From the NASB, with name replacement:
Gen 3:
22 Then Yahweh Elohim said, “Behold, the man has become like one of Us, knowing good and evil; and now, he might reach out with his hand, and take fruit also from the tree of life, and eat, and live forever”— 23 therefore Yahweh Elohim sent him out of the Garden of Eden, to cultivate the ground from which he was taken.
Who is Yahweh talking to? Must be other sons of Elohim. As Gmirkin says, this could be taking place in the divine counsel. But if so, surely the divine counsel would have been introduced in the story. I simply don't think the writer would have left so much to the imagination nor would they have left so much to implied assumption based on prior lore. Surely this was a story that sought to explain everything.
As such, the story must have explained who Yahweh was talking to at some point. And you can't go back to Plato to understand who Yahweh is talking to, because Yahweh doesn't exist in Plato's works. So there must be an intermediate longer story.
The "Us" of Gen 3:22 must be the same as the "sons of God" mentioned in Gen 6:2 & 4.
Where might this lead?
It is important not to put the cart before the horse, and I can't make assertion simply to reach the proposed conclusion.
If it is the case that there was a Hebrew proto-Genesis, i.e. not simply
Timaeus, but a longer Hebrew narrative, then would such a narrative not go a long way toward explaining the development of Gnostic accounts?
Gnostics essentially claimed that Yahweh was a liar, and that the Jews had been fooled into believing that Yahweh alone was the creator of the cosmos and humanity. However, they claimed, the "real story" involved many more actors. They claim, essentially, that the story in Genesis is a redacted and biased version of the real and much longer story.
Enoch essentially make the same claim, though in a different way.
Jubilees is interesting, because Jubilees harmonizes Gen 1 & 2 and gets rid of all the distinctions between Elohim and Yahweh. Jubilees also eliminates any talk of sons of God or "Us" and "We" type references, making for a much more clearly monotheistic account. Obviously, this was an issue of concern.
So is it not possible then that first century Gnostics were working from traditions that could be traced back to knowledge of such a proposed proto-Genesis?