***I wonder what possessed them to think they were remains that would belong to the Caddos or Wichitas?***
Well, that would made *some* sense. Especially considering the bois d'arc bow wood - however, that's all over eastern Oklahoma and east Texas.
And their ancient lands are not where their reservation is now - although they were just a little farther east. I've lived in the Osage, but don't know much about the tribe in prehistory.
In the back of my mind, I think they are possibly Iroquoian in language family - more like Cherokees. Could be wrong about that. I don't believe they are Muskogean or Caddoan, however. Perhaps our Freeper O.O. will correct me.