"I know they are nearly extinct and are seriously discriminated against by the mainland japs. I doubt very much that the situation was completely the reversed only a short 100 years ago." Can't say for sure myself, just something I read. Remember though that 9,300 year old Kennewick Man is believed to be 'mainly' of Ainu descent. (James C. Chatters, Ancient Encounters)
I don't think so. Kennwick man can't be of ainu descent because kennewick man came first.
Maybe what you meant was that both kennewick man and the ainu are descended from the same ancient race.