I'm concerned that that title of the mod is being misunderstood again. The point is to foster diversity between civs, not bringing world diversity into the game; so I'm not looking for geographic or ethnic splits for their own sake. At this point, I've resolved to wait until there is a valid, quantitative reason to expand on the groups (because the Tribal American split works as is, unlike as did civs like Israel originally), so the matter on the Tribal American split will be re-addressed when it is necessary and worth the workload.
The Tribal American group won't be re-named to Native Americans, as that would preclude civs such as the Tupi. I understand First Nations isn't a valid name, either, so I won't be using that. At this point, I'm most interested in splitting Africa, but would also like to see more work done to expand the groups. The Andean group doesn't have a quantitative justification (the High-American group as is is only 9 civs, and all are perfectly apt to belong), but the Inca are a personal favourite of mine, so exceptional powers do apply.