Galactus is indeed the boss for MVC3!
In other news , when beating the game you will be able to unlock a 3d character model viewer! Here's one to get you going !
In addition to the character model viewer, there will also be a mission mode that allows players to learn moves and setups ala Street fighter IV's challenge mode
With the main rooster being revealed capcom has also announced there are still characters on the way, most likely being DLC.
Two weeks to go get hype!
*Slight update
Here is a video showing off all current known hyper combos