I've been doing a little research into a Fulton family from Derrylane, Drum. A James Fulton married to Jane Scott. James's father was called Thomas.
If you look up the previous discussed marriage of Joseph Fulton to Elizabeth Fulton, Joseph's father is also called Thomas.
Also the marriage of John Quigley to Margaret Fulton, Margaret's father is also called Thomas.
I also found the marriage of a James McCully to a Martha Fulton of Drum, again Martha's father was called Thomas.
It's maybe just a coincidence, that the name of father of these Fultons, from the same area, was the same , or maybe they were all siblings, although the difference in marriage dates makes it a little unlikely.
Going back to the McCay connection, I think a son of James called Thomas Robert Fulton, married a Margaret McCay from Drum in 1909. Thomas and Margaret had a daughter called Martha Quigley Fulton.