Coming from a Catholic, the whole priest abuse angle is kind of a lame insult anymore. It's too played out. Confusing them with BYU could be good. Asking when all of their players take their missions, etc. Also, logical fallacies in the bible would be good bait. I've toured the Basillica on their campus, and they take great pride in having relics. A splinter from the true cross, bones and fingernails of old saints, etc. And for whatever reason, ND fans are very proud of certain alumni like Regis Philbin and Dickie V. A lot could be done with that.
