Hello John. Here's what I found about this family in the Oldcastle parish records.
John McCleary married Catherine Murtha 27 Jan 1839. Their 3 sons were born as follows:
Anthony 12 Dec 1839
Christopher 3 Apr 1842
James 10 Jun 1845
I don't know about a connection between the above family with that of James McCleary and Rose Fitzgerald, but here are their dates:
James McCleary married Rose Fitzgerald 10 Jan 1821. There children were as follows:
Bridget 10 Dec 1821
John 22 Feb 1824
Mary 30 Jul 1826
I don't know if the John who was born 1824 is the same as the John who married Catherine Murtha in 1839 are the same person (he would be not quite 15 years old), but such an early marriage is certainly possible in that time and place.
These are 2 of the 12 families of McClearys that I extracted from the Oldcastle records. Presumably they all connect in some ways that I haven't found. If I can unite the family of James-and-Rose with that of John-and-Catherine, then my database will make a lot more sense.
I'd appreciate any new data or sources about this family.
Jim Ross (Mirkes)