I personally like kings lists-they help me to think about how these different rulers would react to the larger historical events and it helps to flesh out details to the polity.
Well you could make it so they are seen as just a different "tribe" of humanity since they are so similar and can obviously procreate with humanity. There would be some genetic differences of course, but not anything too wild. If you wanted to go into a more lore aspect, Neanderthals could be recognized as different and oppressed in certain places (not because they are seen as genetically different obviously but rather the view that they are a different "tribe") and other places seen as sort of special. (think of the notion of royal families and that sort of bloodline) You would also have to geographically separate them from regular homo sapiens in some way to prevent the intermixing that would just create, not Neanderthals' on a large scale. This would occur anyways but if you wanted to keep actual Neanderthals alive than this separation would probably have to occur.Honestly? just eyeballing it and drawing inspiration from real-life paleogeography. Also GProjector.
Yeah but im still not sure how to incorporate them yet.
Quick question for everyone, would you rather I list every ruler of the major nations in the timeline or just the ones that are important? I'll eventually post king lists too if people are interested.