Sonic All-Stars Transformed, which characters will the Vita get?

A Sumo Digital producer's post on the Sega forums suggests that each version of the game will have a few unique characters to add some distinction between the platforms.

"Over all the different platforms, this totals up to 29 actual playable choices. But that doesn’t mean that there are 29 playable choices in all platforms (in fact no single platform has all 29). Some drop down to the low 20′s, some instead have high 20′s."

So, alongside PlayStation All-Stars, we have another game where we'll doubtless be drip-fed a character list. Wonder what the Vita will get as its exclusive roster line-up?