How do i get the regular costumes such as mega mans blue form? Also why is wolverine in there twice just with a bit lionger claws?

Not quite. One Wolverine has bone claws, while the other has adamantium claws. I'd rather have another unique character too. 
 
Other costume decisions depend on what button you press when selecting the character.

AgentJ has it down pat.
 
i actually choose both wolverines if the other guy chooses a god team (Magneto,Setinel,Storm)
 
its the only way i can take out setinel quickly and leave my akuma to finish the job

For people who really like Wolverine I guess. Why settle for having one Wolverine on your team when you can have two? 
 
I hope the sequel has three Servbots and four Dans. That'd be great.

Bone claw Wolverine can do the Tornado Claw in the air, which Adamantium Wolverine can't do.  I'm not sure if there are any another differences between the two.

LP/X/Square is almost always the primary costume in fighting games. Haven't you ever played a fighting game before?