Iowa Derby's...Keokuk Area

I am interested in the line of William/Chancy Derby. Elizabeth Anna Derby was my greatgrandmother. I have found her tombstone in Kansas. Next to her is a stone with J. H. DERBY and W.F. DERBY. I assume J. H. is JOHN H. DERBY, her brother. Does anyone know of a marriage to JOHN?

I also have photos of stones in Iowa that haveFRANK L. son of H.C. and S.R. Next to this stone is another that has, The Son of H. G. and S.R. Derby. the name is hard to read but could be CLARENCE A., died at 7 months old Sep 20, 1875/78?

Does anyone have additional information on any of these Derby's?