Source: This is pure speculation based on the fact that when he moved into the Vow (according to the Tithe Applotment Book), John Coulter's next door neighbour was a John Hannah, and I know that John Coulter married a Mary Hanna, so it seems possible, perhaps even likely that he married the girl next door!
John Hanna held 18/0/1 arps in the TAB. By the Griffiths Valuation, a Thomas Hanna is the only Hanna holding land in the Vow. Is he a son?
BB: I notice there is a John Hannah in Vow and Artnagross just like John Coulter (TAB).
I could NOT check Cam in either the Camus TAB or the Macosquin 1831 Census as it and a couple of others are missing from one missing page in the TAB and about 15 townlands, including Cam are missing from the beginning of the census.