I believe Thrope was Sac & Fox...mostly.
Yes, I live in OK...Like Thrope I had great aunts and uncles that went to Indian Schools..and that ended up working at them also. Mostly at Chilocco Indian School...North of Ponca City, OK.
FWIW-
My family was friends with Stan Snake A Ponca Indian (and Mormon) from Oklahoma. He recorded an album of his music out at BYU and was involved with the Lamanite Generation out there. He carved Flutes. He passed away a few years back from health problems. Early 1990’s I think.