Additionally, what was the fate of the more polytheistic roots of religion in the area? I read that Yahweh gradually gained the qualities and powers of former Canaanite gods and was curious about any resistance to the process.
Yes, there was resistance. Actually most of the bible between Exodus (or rather Genesis) and Psalms is about that resistance and how Gods choosen battle it.
Exemples:
The golden calf, raised when Mose got the commandments.
In The kingdom of Israel there was a strong moment against monoteism, se Kings 1 & 2.
1 & 2 sam do describe how the jews did wellpapp when they followed Yahweh and suffered when they went after Cannanite religions.
and more.. The bible am full of the resistance against monoteism.
The resistance is also confirmed by archeologic evidence, like old housegods and fertility-symbols. (do not remember source, but it's no controversail in any since).
Most of the polyteistic religions lived a long time and did merge into bigger polyteistic religions, like the greek. Just in the same way as greek and roman religion did merge. After greek did become rulers of modern Israel, I have no memories of that Baal am named in any place, bible or other sources.
I do not remember that any of my books describe when and how Yahweh did get describe with more attributen, so I do stop here.