Ginny, Glen and who ever else may be researching Chief Joseph, I am not related, but have/had family in The Palouse area, so have done research. And in the proccess read a book called, "The Tekoa Story, From Bunchgrass to Grain, 1962". Not sure which family history story tells the part about the Chief and his family, but will take a look at the book if you like.
This post is not a recent one,so don't know if you still what this info.
Good luck, Chris in Spokane County,WA.
You may reach me at firstname.lastname@example.org