Been following this for a while, but finally joined Eurobricks to put in my two cents here.
I think we'll see lots of classic, non-Princess figures at least while the Princess minidolls are around.
My guesses?
Mickey, Donald, Goofy, Minnie are shoe-ins. And I feel like it'd only be right if Mickey came with a pluto accessory. I mean, the Simpsons minifigure series gave us the whole family each time.
Winnie the Pooh (with the bumblee girl's honey pot?) and Tigger (with the tiger girl's new tail piece)
My guess, like others' is that it'll be focused on classics. Peter Pan and Tinkerbell. Hook's a possibility, too. I could see Tinkerbell being a full-scale figure, given that she has her own line of movies. Alice and the Mad Hatter would be great choices. Baloo and Mowgli? Cruella? Pinocchio? Scrooge McDuck? Robin Hood?
It's also Disneyland's 60th anniversary this year. It'd be interesting if they do a set like the Disneyland castle to go along with this series. It'd make sense, then, that they make this line of figures more like the theme park representation. All in the same scale, despite the character. Which opens it up to a minifig Pluto, Chip, and Dale. If that's the case, though (and this is all wishful thinking), I'd love a normal boy and girl with a mickey balloon and mickey ears accessories! And if it was park-focused, it'd be cool to get representations of different rides (hitchhiking ghost from haunted mansion or a pirate from pirates of the caribbean or a skipper from the jungle cruise or a country bear).
But, obviously, this is all just speculation on my part. I've never been so interested in seeing a lego series before, though!