Mewtwo is going to come out sometime during March, 31, 2015 Or 3/31/2015. Sometime later there will be paid dlc for Mewtwo. You can get Mewtwo by registering both Wii u and 3ds versions of Super Smash Bros on Club Nintendo.
MEWTWO'S MOVESET:
Aerials: Mewtwo will probably have the same aerials from melee here is a picture of the aerials
Specials: All of Mewtwos attacks will be the same his standard special will probably be Shadow Ball. Side special Confusion. Down special Disable. and Up special Teleport.
And his final smash will probably be mega Mewtwo Y