Hi Roger, I see 3 James McGinniss including one James McGennis married in Louth between 1840 and 1850, am assuming you have births of children giving the mothers name to verify the 1845 marriage. The problem we not have is that a parents name to locate any birth record, do you have an approximate year of birth,
There is a James born in Haggardstown but no brother Thomas (in the search he has one sibling Ned (Edward) mother is Brady, however there is also a Thomas born in Haggardstown with a mother Boyle, a number of siblings, could theybe cousins, I attach the two records below from a subscription site.
Name: James Magenis Date of Baptism: 08-Jan-1812
Address: Thomastown Parish/District: HAGGARDSTOWN County Co. Louth
Denomination: Roman Catholic
Father: Owen Magenis Mother: Catherine Brady
Informant 1: Patt Mathews
Informant 2: Nancy Clerk
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Name: Thomas Mcginiss Date of Baptism: 27-May-1809
Address: Mahorriah Parish/District: HAGGARDSTOWN County Co. Louth
Denomination: Roman Catholic
Father: John Mcginis Mother: Margt Boyle
Informant 1: Hugh Craven
Informant 2: Margt Mccooye
I cannot locate the 2nd placename as it is either an old spelling or not turning up on a civil record of the area, relgious parishes were not exactly matched to the civil parish of the same name, you can see the actual registers here, search by year and month onlyhttps://registers.nli.ie/parishes/0215 you can see the civil parishes and townlands here, Thomastown is probably much more developed now that then. https://www.townlands.ie/
There is an interesting site about Louth here http://jbhall.clahs.ie/
Revert if you think there is more can be sought.
Regards
Pat
