i didnt read everything, but i just want to point out, not so long ago, there where 3 types of humanoids living next to each other
homo erectus, homo neanderthalis and homo sapiens.
why 2 of those are extinct.. no one knows (yet) but my theory is that homo sapiens are very good in adapting to new environments, maybe those other 2 humanoids wheren that much adaptive. it can be very good possible in the next million years other human species will develop out of us, the homo sapiens.
there was even a time when 4-6 humanoid species where living next to eachother.