I've discovered a lot of family baptisms and marriages on Catholic Parish Registers at the NLI in trying to research a first and second marriage with quite a bit of success especially when you know a place and dates to search around. I recently started a notebook just to record family names in Navan to see if I could connect the dots that way, too.
Not sure if you've used this site, but thought I'd share their link just in case you hadn't. I bookmarked their link below because it's so handy. Good luck with your search!