Yeah, Dabura, I forgot about him, and others... maybe Garlic Jr, Omega Shenron or Janemba. Pikon's not that important to me, and yeah, Cooler would be good to have there, and also Android 13.
I'm not that good with Kid Buu, but he's really annoying to fight against, so I prefer Burter. Well, you can do the same thing with normal Goku and SSJ Goku, but SSJ2 is just more powerful, so I use him. But Vegeta will always be my favourite character.
Nah, using SSJ2 Goku is better, you should try what I said.