Is the man on the left the same man on the left of your second photo?
These are Elliott and Fry photos and I have to admit, I haven't seen any of them before. I believe the National Portrait Gallery in London has their archives, although I seem to remember the only relevant photo featured in their online stuff was of Cody.
Looking at the Kasebier book, I think the taller man next to Joe Black Fox is High Heron; the man standing at the left of the photo may be Amos Little. Short Man or Has No Horses sitting at the far right?
This is the second time I am typing this. the first one disappeared before I could post it.
May 1, 1887 R. A. Horse writes in the Iapi Oaye newspaper. Buffalo Bill show at Philadelphia, PA.
11 cloth tipi's, one big tent (Circus Tent?). Six women, one a Scila Winyan (Pawnee Woman). three big men (leaders) Wasicutasunke (American Horse) he is the boss. The other two are Zuyahusta (Lame Warrior?) and Peyucancanpi (Shaking Medicine? (the y is probably a mis placed J) There are Shoshone, Pawnee, and Lakota (Oglala) performers. The article goes on and on.
The March 1, 1888 Iapi Oaye has an article by Black Elk with Buffalo Bill in England.