IGI has them marrying in Arbory 23 Nov 1805...so they were likely born prior to 1785.

KISSAG, Richd s/o John KISSAG & Ann CORHAN chr 13 Apr 1783, Patrick, IOM is the most likely.

John KISSAG m Ann CUBBON or CORKAN 17 Dec 1780, Patrick, IOM

John possibly s/o Wm & Esther GARRETT chr 13 Apr 1755, Jurby, IOM

Closest Catherine LEECE is:

d/o John LEECE & Margaret CAIN chr 15 Feb 1793, Kirk German, IOM (which seems far too late)

but there are a few Catherine LACE possibles, including d/o Daniel & mary JOUGHIN chr 22 may 1785, Ramsey, IOM.