I believe they will announce zurg, Ferb and the green car from cars 1 (sorry don't remember his name), I know it might sound odd but They have been hinted as playable characters in a number of trailers
My prediction
The starter pack will have a character from avengers, gardians of the galaxy and a character from big hero 6
I believe it will be a new disc (most likely true)
Another prediction I have is the marvel play sets will be cross playable but the characters part of the play set are the only ones to unlock vaults, plus this will fix the common problem of kids not being able to play co-op from the box play sets.
Random prediction
All the play sets crystal world things will be coloured red for marvel.[SMILING FACE WITH OPEN MOUTH]