Good list so far, not a lot to add except a few notable songs.
Seven Nations, IMO, was moving that way especially on "Thanks for Waiting"
Some Enter The Haggis, notably "Litter and the Leaves" from "Gutter Anthems" has definite punk undercurrents.
I have to clarify that I wouldn't classify either group as being Celtic Punk per se. Just listing a few individual songs that may fit into that genre.
I have two modes: wiseass and dumbass. Mode is determined by current blood alcohol level.
Drinking is a sport. In order to be competitive, you must practice on a regular basis. Although you can practice alone, it is much more fun to practice with friends. If you're out of shape and practice too hard, you will regret it the next day.
Life is a disease. It is sexually transmitted and always terminal.