I was going to make my character half Irish half Japanese too, I'm Irish myself, but I figured it'd be too awkward. You pulled it off pretty well, though! Only problem is that there are no high schools in Ireland, they're known as secondary schools. There's really no Japanese people, hitmen, people named Edward or prostitutes either, but it'll do.
One more thing, saying that he has a heavy Irish accent doesn't give much insight, as the range of accents in Ireland varies so much that you could seriously drive for 15 minutes here and end up with people that sound like they're from another continent. But hey, you can't know everything about another's country. Aside from my rant, everything is great there, hope to see you in the roleplay!