Minecraft on PS Vita will be based off the Console Version, not Mobile
Mojang developer Jeb has said that the Console version will be the base for the PS Vita version of Minecraft in a Reddit thread.
The Vita will use the code base for consoles, and not from Pocket Edition.
The Pocket Edition of the game, designed for mobile devices, is an edited down version of Minecraft, and lacks some of the more recent features, including generated structures and updated biome generaion.
In contrast, the console edition is a bit more up to date, although it does still lack some of the features present in the PC version.