As for skin colour I used a range of paints. Bugman's glow from GW, get used a lot by painters, so I used this as well as the Foundry Native American paints. Once an ink was added to shade the skin, I highlighted the skin back with Bugman's glow.
UPDATE: I decided to tweak these guys a bit as I'm not convinced with the blue. In all my references for Woodland Indians, I can't find any blue warpaint.