Mostly, I think the place I disagree with you is that you see the beliefs as primary and the tribal membership as contingent on beliefs, at least when it comes to Judaism, and I see them as largely unrelated.

That is, I no more decided to be Jewish on the basis of religious beliefs than I decided to be American on the basis of national beliefs, and being Jewish no more constrains my Saturday activities than being Hispanic does. They are all affiliations I was born into and choose to endorse, despite not practicing them in traditional ways.