Hello Carol,
Your William Sr. may be a brother to a Cash Jones who married a Cora Jackson ... they are the in-laws of Margaret Louella Lancaster, my 2nd cousin 1x removed.
Harold, one of the 9 children of Cash/Cora, & Margaret Louella (Lancaster) Jones lived in Paulding and Champaign County, OH at various times. They also had 9 children, some born in Paulding, while others were born in Champaign.
I have more detailed information on Cash Jones and his family (parents & siblings) if you are interested. For starters, these Jones' were originally from VA, but found in the 1880 Census living in Delaware Twp., Hancock Co., OH. A Cashes & a William are listed among the John & Mary Jones children. "Cash" appears to be a nickname for Cashes (sic), Cassius.
I'm unable to answer your questions about Darke county and the families of William/William, Jr., but I'm sure Doug will have some information on them.
Hope to see you and your friend at the AAGGMV meeting on the 15th, if not then, perhaps at a future meeting.
The URL below has a map of Ohio counties and the county seat for each. Notice the proximity of Paulding, Champaign, Hancock & Darke counties. Also during the years you are speaking of there was a HEAVY A.M.E. influence in those areas.
Art Thomas