In response to your query regarding the location of the McCullough Cemetery, I checked in the book compiled by the Ohio Genealogical Society called: Ohio Cemeteries: 1803 - 2003. On page 309 in Prairie Twp I found:
McCullock (5650) Sect: S36. Location: 200 feet south of TR 243. On TR 193. First lane turning east. Jonas P. Stutzman farm.
Jonathan Grant is listed in the Holmes County Burial Record book. I assume the cemetery is still there. You may need permission from the Stutzman family to access the cemetery though.