Some native American's are very light skinned as per the north western people as they mainly lived in the woodlands part of America. From Bob Knees (A highly respected miniature painter) article on American indians. I highly abbreviated the following.
Depending on the section of country the skin tones varied accordingly. English observers noted that they looked like Englishmen that are well tanned referring to woodland Indiansl . American southwest Indians have a venetian red hue tone. Northern plains have a dark tan (not red).
With oil paint the mix to start is Yellow Ochra + Burnt Sienna +Caucasian flesh. This basic flesh mix + a bit of cadmium red light to pink it up. You can use venetian red or terra rosa to tint the flesh a little more. Add white to your taste to lighten. Even burnt sienna will darken the flesh a little more. You can use similar colours if using acrylics and adjusted to your liking.
There is no true American indian flesh colour as such.
I hope that this will help you a little and look forward to seeing your finished figure.
Cheers
John