Do you mean Anna and Elsa? They now meet in EPCOT at the Royal Sommerhus, and there is no FP+ for their meet and greet. The Frozen Ever After attraction is the only Frozen experience at WDW with a FP+. I have only seen the meet and greet line reach 60 minutes, but if you are there during the beginning of the day, I have seen it as short as 20 minutes.