I believe I have been acquainted with your daughter on Facebook. Fred and Sarah's son Edgar was my 2nd Great Grandfather.
Information I have on Sarah -- her parents were Jeremiah "Jerry" Thompson and Louisa Whitcomb. Louisa's parents were Adam Whitcomb and Susan Steinmetz (German), which means Sarah probably not 100% american Indian, but pretty darn close. I do not know who Jerry's parents were.
Sarah re-married for a short time after Fred's death to a Henry? Kalinski in Chanute, Kansas. She was born in Upper Allen, Cumberland, Pennsylvania (not Allegheny like her obituary says). From what I know of the area, she was most likely descended from the Delaware tribe. There was a Charlie Thompson I found in my research that was half-white, half-native American who was once an Indian Chief (not sure if there is any relation).
Sarah was the eldest of all her siblings: Andrew, Adam, Jeremiah P., Caroline "Carrie", Josephine, Eliza, Amanda, and Mary "Mollie".