Not Chief Dan George, he's great! Too bad he didn't make more movies. He has some other credits but the world remembers him form that one and, even moreso, for Little Big Man. Eastwood must have liked him because he reputedly had an awful memory for lines, which doesn't really sound like Clint's kind of actor.
I think I pointed out that the book was by Wallace's speechwriter when you asked me about the movie last month. I forgot that he used "Forrest" as his pen name.
In Jim Kitses' book Horizons West, Directing the Western From John Ford to Clint Eastwood, he's mostly very positive about the movie but criticizes "the film licking its chops over a protracted near-rape that gratuitously strips the woman from top to bottom."
There are actually two call-backs that come to mind in Unforgiven. When Eastwood decides to take up the bounty job he gets out his six-gun and tries to practice with it like Josey did, but he gets frustrated at his own shakey aim and blows away the target with a shot gun. The other one is less blatant, but after the climactic gun fight the novelist character asks him how he knew who to shoot first in a gun fight and he says "I was lucky in the order."