It's a fictional tribe, they can pull anything out of their butt they like.
Maybe. But I think only to a certain point. Many of his native "traits" were very derivative of stereotype and very Native-lite
. So even if they drew bits from different tribes and what not, they could have tried harder is all I'm saying.
Chakotay could've sung the Disney's Peter Pan's "What Makes The Red Man Red" and it wouldn't have made his character any less offensive. I find it funny that they made Chakotay the guy who broke up Tom's gambling pot in the season 2 episode "Meld". A Native American who has a problem with gambling. All Chakotay was missing to make his stereotype Indian character complete was to be a crippling alcoholic.