I too have a John Wilson who married in Enniskillen in 1872. Mine was son of William, while yours reportedly was son of James. My John Wilson was widowed in 1875, seemingly without children. His late wife, Annabella Noble, was my great grandfather Robert Noble's sister.
Too bad we didn't match up. I hope someday to figure out whatever happened to my John Wilson, but the name is frustratingly common. Good luck and best wishes