The same Horatio Nicholes is listed twice in 1860 in Marion, Grundy County, Missouri. Both times with Mary but the other says Mary A. Nicholes 32 Indiana and says Horatio 34 born Indiana.
Evidence suggests that Horatio, William & James are related, most likely brothers.

Also Horatio's marriage to Mary Price is 16 March 1848 Scioto County, Ohio.

William's wife Elzira, Elzara, Eliza whom he married 12 Nov 1859 Scioto County, OH is listed as Ebzira Heflin age 9 KY with her father Wm Heflin 51 VA and siblings in 1850 US Census, Fleming County, Kentucky.