I realize that I am 13 years late to the party, but I am currently working on rules for a North American Pre-European TTRPG, I am, in respect to Native Americans, not using exact nations but nations inspired by the historical. Not being born into the culture I do not wish to cause insult anyone by any well meaning mistake. I would be happy to get feedback and share opinions on the subject.
Hate to say it. But this wont save you. You have to remember these SJWs are insane. You cannot appease them. You cannot win except by making your game as you want it. Not as you think will please some bigots and lunatics.
You use real tribes and locales? You monster! That is appropriation!
You use made up names and locales? You monster! That is exclusionism AND appropriation!
You replace them with Dinosaurs... You monster! That is exclusionism AND appropriation AND whitewashing as you are obviously not a velociraptor!
Oh and we are on to your dirty little secret that the lemurs the velociraptors are struggling against are really representations of the oppressed black minority and your dinosaurs are the priviliged white males!
I'd love to say any of this is an exaggeration. But in the last two years alone all of the above have been levelled at games at some point, and more.