Thank you for all your comments. I am very glad that so many people reacted! To be exact, listed champions are the only mutants I have as 6* (not counting 6* Deadpool, I was lucky to find in the crystal recently ). I also feel that Red Magneto is a safe choice to go. But what about Bishop's Power Transfer and Regen? I am thinking a lot about amount of potions I will be forced to use per mission.
Definitely Rdd Mags. He wrecks.
Dude, place Domino everywhere. If she is duped, she will do some damage. Why do you skip her? Also, if this is all you have, then rank Bishop or Magneto and ascend them with Signature 200. You will not regret it. Toad is an easy defender. All others can be defenders and attackers. Don't go for Professor X because he is overrated.
I want to thank everyone who was participating. I decided to roll with Magneto. Feels awesome to see those SP3 numbers.