More than likely, based around what has happened with the Halloween Party, IMHO, it's a good bet that for Anna & Elsa (Olaf and more?), you may be seeing an announcement in the near future that they're going to be part of some Frozen Soiree that will be an additional cost on top of your additional cost of the Christmas Party and it might be more than $99 that they are currently charging for the VSS. The Christmas party is a little higher cost than the Halloween Party and given the demand for A&E, if Disney were to go ahead with a Frozen Soiree type event at CRT, I could see it easily being over $99 for parents to "buy their way out of a line". (I'm not an expert, I've only read the rumors, and seeing how Disney did this with Halloween, A&E are huge right now, and it would only make sense that they would do something like this, take my opinion as just that. Opinion.)
They added the Villains Sinister Soiree and took the Evil Queen, Dr. Facilier, Maleficent away from the M&G's. Dr. Facilier was at the Villains Dance Party in Frontierland, but that's not a true M&G for posed pictures and autographs.
Having just gotten back from WDW, the line for their M&G at PFH was under an hour. Whether it was that way from a decent balance of FP+ and paper return times, I don't know. It wasn't the heaviest crowds, but they still had decent wait.
