Love the bases for them all, but I think that some of the cutie marks are too complex. Just one thing would make it seem cleaner, and Jasmine's.... doesn't really fit. I think maybe one of the birds she kept, or the flower Aladdin gave her. For Pocahontas, what about the windblown leaves? It would leave a different feeling to it. I do like Snow White's though.
Don't know what you mean by 'tribal' but these are not the Friendship is Magic characters dressed up - it is what the Disney Princesses might look like if they were ponies.