It will be a great experience and someone will volunteer or make sure you get your "portrait" taken.
Unfortunately (at least for Disney World), unless you go to 1900 Park Fare (dinner only - Prince Charming), Trattoria Al Forno (breakfast only - Flynn Rider & Eric), or the
MVMCP (maybe the
MNSSHP too, not sure), you likely won't find the princes to meet.