Hi, I went through the St Mullins births from 1792 and the marriages from 1796 and the only marriage I could locate for a Patrick Barron was;
Marriage:
Patt Barren & Mary Rickind (I think its Rickens) on 7 Feb 1808
I also did not find a marriage for Thomas.In the baptisms for St Mullins I found 2 with the father Patrick Barren;
Births:
2 Oct 1808 Catharine parents:Patt & Mary Barren
21 July 1824 James parents: Patrick & Mary Barron
I found no others.Bear in mind some records are illegible or are missing. I then looked at the Borris,co Carlow records(its a short way from St Mullins). I have found that many people who have connections with St Mullins also can appear in Borris records. In those records I found only 1 marriage for Patrick Barren on 12 January 1795 to a Margaret Dean. I found no birth for Thomas. Although I did find a few birth records of children born to Patrick Barin and Mary Keating.
Looking at the records I noticed that the Barrons seem to be concentrated around the Borris area and the Pendergasts around St Mullins. If you get anything else I will look further. Kim