The original indians tended to be a bit more dolichocephalic, so the shape of their head was more narrow and long than caucasians. Sculpter maybe is exagerating it, but its not essentially wrong.
Also, take in count that indians didn't invented Tomahawks. They had stone axes, later steel axes, but it were the french who used the tomahawks and the indians took those from them.
So those axes you see in Crusader Miniatures would be ordinary axes, not actual Tomahawks.
Anyway, Crusader tends to make more beefy miniatures with bigger equipment. Just a matter of tastes.