Until there's a reason to doubt anything he's said about himself, I'll leave your comments here but I won't make any changes. No one has accused him of getting any details wrong in his work, as they have, for example, with The Education of Little Tree. There's no evidence that he lied about being a powwow dancer—if so, he's more culturally Cherokee than some people you'll find on the tribal rolls. Your argument seems to be based on whether one search through the records is accurate.

And most importantly so far as the essay is concerned, no one doubted his heritage at the time he was cancelled. You seem to be the first to question it.