It would also be funny to get them to be accountable to Nintendo for their infingement on the Pokemon character.
Watchtower is really in a box with this one.
As far as the Pokemon character goes, I'm not aware that the actual spelling of the Warrior Wizard's name has been officially confirmed, and the character is probably different enough to not infringe on the proprietary interest in the Nintendo character.
A fictional villain (if a metafictional plastic toy can really be called a 'villain') is still intellectual property. The shirts might be arguable as satire, but it's a pretty fine line.