I don't care for the Irish National Heritage Park. Dunbrody is interesting and if you like seeing the crystal making process the new House of Waterford Crystal is a good walk-through overview.
Going north doesn't seem to make a lot of sense. Too much traffic, figuring out the M50 tolls. Newgrange would take most of the day.
Have you looked at your line of travel? Some things could be done on your drive to Kenmare.
I agree with Michele. Option 3 would be my #1 choice. Wexford, in my opinion, is okay, but not really all that interesting. Dunbrody is relatively more interesting, but not more interesting than Powerscourt, Glendalough, and Avoca (Meeting of the Waters).
Option 2 would be my 2nd choice (minus Dunmore Caves, unless you really like caves). The best way to experience Kilkenny is to walk it, and there is enough to see that you'll be busy for a whole day, if you see everything. And I'm a big fan of Rock of Cashel and Cahir.
Option 4 would be my 3rd choice. Which leaves your Option 1 as my last place finisher.