Later census show his parents were in fact b. VA. He's found with family in Benton, IN (which I think you know) in 1870 & 1880. Their daughter, Julia, was 10/12 in 1850, married name of Williams in 1870 with a son, Ernest, 2 mos. (Apr birth) living with her parents, then back to listed as Julia Morris in 1880 (married-housekeeper) with only father and siblings - no child. Did you figure out who she married? There were a number of Morris H/H in 1830-1840 in Ross county OH. A couple came from VA and had children the right age to be John. Have you tried making the connection through the McMillan line?