The early religion shows sign of diverging into two cultures: one who called their god Elohim, and the others called their god Yahweh, who was recognised as a god under El.
Good post. I have a little to add.
I think they were already two cultures, not diverging from one. Israel in the north, who were elohists, and Judah in the south, which was a yhwh cult. Israel was destroyed and a lot of people from the north moved south. They needed a way to blend the two similar but distinct people. It was typical in those days for conquorers to accept the gods of the conquored into their pantheon. So the Judaeans, though not conquorers, tried to combine their stories. they tried to make it sound as if they were all one people, long ago. In fact, they said they had all been slaves in egypt to give them a mythical common tragedy.
It was simple enough to do since they had similar stories, but different heroes. This is why in the bible you so often have two similar, but slightly different stories one right after the other. One is the story brought by the elohists, the other by the yhwh cult. The hero of one (judah, I think?) was Moses. The other's was Aaron. So, they made them brothers. The Judaeans had more sway, so Mo was the older, more important one.
This was not done all in one fell swoop, but over many years. Politics shifted and different factions had power at different times. Sometimes an Aaronite, sometimes not. So the editors put emphasis on the things they valued and generally tried to smear the things they did not. Sometimes it was the priestly rituals, other times it was making one group or tribe's hero look good, or bad. Lot getting drunk and impregnating his daughters is a good example of that.
A good book that covers this is Who Wrote the Bible, by Robert Wright. I believe you can find a free PDF of it online. I just got it from my library, but it is probably a good book to own.
There is more evidence to Iaac being sacrificed than just that, though. For one, the language at the end of the Binding story suggests Abraham went back down the mountain alone. Genesis 22:19 says :
"Then Abraham returned to his servants, and they set off together for Beersheba. And Abraham stayed in Beersheba."
All the verbs are singular in the hebrew. That's because Isaac's ashes remained on top of the mountain.
And you don't hear from Isaac again. In later stories, Isaac is just a bridge to Jacob, hardly worth mentioning.
Secondly, child sacrifice was practiced by early hebrews. That is one reason why the OT talks about redeeming first borns.
Third, all the polemics against child sacrifice make no sense if nobody was sacrificing children. They only make sense if it was a problem they were trying to address.
Last, they actually believed child sacrifice worked. In 2 kings 3, Mescha, the king of Moab sacrificed his firstborn son on the walls of the city and it allowed the moabites to turn back the invading Israelis. Also recall Jephthah in Judges 11 sacrificing his daughter, Mizpah.
Ref - Human Sacrifice in Jewish and Christian Tradition; Finsterbusch, Lange, Romheld; 2007