Amazing work again.
If anything, the poney tail could use more contrast between the light and dark in the hair.
And the hair on the indian chiefs head, wasnt as well combed as on your image, but hey wouldnt have thought of it, if I had not seen the photo you referenced to.
I have seen a lot of great photos of native americans, indians, many times taken by E. Curtis on my trips around Arizona state in the USA, and then in books back home in Sweden, and exhibitions. E.Curtis took great photos, and you would have made E. Curtis proud!!