Nothing more about his ancestors.The comment I made in 2010 about William I possibly having a brother or other close relative named James is the only piece I can offer. I have no idea where this record of him and James came from or where one might be now. There's no other info about his lineage that I know of.His own son James, in The Ohio Genealogical Society report of Winter 1978, mentions that he knows "nothing of my progenitors beyond my own parents."
If there were any written records here in the States that might have given us a clue, they were probably kept at the White Clay Creek Presbyterian Church in Delaware. However, a fire destroyed all pre-1900 records. I don't know when the fire occurred or at which church (old church or new one built in 1855). The only comment I see about it is "all records prior to 1900 were lost."
William Addy (I) is my GGGGgrandfather. My lineage is: Me, son of Thomas Hugh Addy (7 April 1937 - 8 Dec 1983) and Gail Francis Boucher; Thomas, son of Hugh Reed Addy (12 Oct 1893 - 14 Dec 1975) and Florence May Inez Berry (30 Jul 1896 - 12 May 1971); Hugh, son of John Ross Addy (Apr 1862 - 30 Sep 1894) and Margaret Ann Cullen (6 Aug 1869 - 11 Aug 1959); John, son of Hugh Addy (13 Sep 1821 - 12 Jul 1903) and Margaret Warden (2 Sep 1832 - 6 Aug 1898); Hugh, son of William Addy (II) (1781-1857) and Wealtha Ann Jones (1787-1848); William (II), son of William Addy (I) (ca 1750-1827) and Elinor (Eleanor) Clark (ca 1753- ); William Addy (I), son of ???
All dates I've listed here are subject to (mis)interpretation(!) but are generally close enough for me. I'm sure there are more exact dates floating around here for some of my grandparents.