OK, so the earlier Martha was Mccullin, the mother of an earlier 4 children, and the William Callister & Margt Kermeen were a different family in Patrick. Which leaves William Callister no.3, the father of James Callister bapt 18 Sept. 1842 in Patrick, with mother Martha Kermeen. This was the bapt date given by Karen. Three William Callisters around the same time, with two of them married to different Marthas, and two married to Kermeen.

When/where were William & Martha Kermeen married, and where were they living?

Sue