Amazing image! Fascinating...

Upright feather bonnet headdress?

@Mike Blake, yes unheard of for a Northern Cheyenne society (Elkhorns, Kit Foxes or Crazy Dogs) but this is likely a Northern Cheyenne warrior who joined the Dog Soldiers and this is a drawing of that time, or perhaps a Dog Soldier who came north after the Battle of Summit Springs and was then involved with the 1876 battles. There are many instances of both crossovers happening, and possibly 1/3 of the Dog Soldiers were Brulé and Oglala as well.

A young man visits a woman for courting. Unusual to see horses teeth in this drawing.

Sweet Horse!