1) Levant and Canaan especially are known as the place where sedentary way of life emerged for the first time ca. 15-12 millennia ago (Natufians). Many tribes in Canaan exhibited pastoral way of life, thus they were (sort of) nomadic. But they've done so out of choice, and not because they were forced (well, they were forced by the needs of their stock).

2) Conquest of Canaan by Jews is a myth (see e.g. work of Israel Finkelstein) -- Jews were local population i.e. Canaanites.

3) Native American tribes were a mixed bag -- the form of subsistence included agriculture, pastoralism, as well as hunting and gathering and anything in between. Some tribes were nomadic, some were sedentary, and you could find pure animism as well as hard-core polytheism.

4) Non-dual understanding of reality is definitely a "superstructure" as you say, but one built upon/within animism. Monotheistic religion is then to non-dualism as polytheistic religion is to animism -- an institutionalized appropriation of "mystical" knowledge in order to build a hierarchic social structure. Thus, I call it "core" (without it there would be no monotheism as without animism there would be no polytheism).

5) You don't need monotheistic religion to hold a tribe together or to keep its culture intact as is the case with e.g. Australian Aborigines or Native Americans you've mentioned.

Etc.