Thanks for the information.I know much more now than I did at the time of my original reply.
I found Carolyn Ginther Lerner's death certificate, which lists her mother's maiden name as Kauff.
From there, I found Peter and Elisabeth Kauf (Kaff, Caft) in the Pittsburgh area, close neighbors of Jacob's family (Debolt, Dewald, Dewalt, Theobald), with a daughter Catherine and a son named Theobald (among other children).These Kaufs are from the Borsborn area of Germany, where my family was known as the Theobalds.
Jacob Debolt's great grandmother was Elizabetha Margaretha Kauf, but I have not yet connected her with the Kaufs in Pittsburgh/Mason Co., WV.
I still don't understand the uncle/niece relationship, but both John Ginther and Carolyn Ginther Lerner were close enough to Jacob to testify on his behalf regarding his civil war pension claim.
I believe your great grandmother's ancestors connect with mine somewhere, but I just don't know where yet.If you want to know more, or have anything to add, please contact me directly.