I'm a couple paths away from completely exploring Act 4 myself. The only things you'll have to worry about are probably a 1% per-second healing Magneto in... 4.2.4... I... think? I can find out for sure and get back to you. That duped AA will shut him down though. 4.3 Starburst will be annoying, but nothing that roster can't handle. 4.3.6 Venom might be annoying. Do you have a duped Ronan, even as a 3 star? If so, you can stun-lock that Venom the whole fight. If not, I see no other counters in your roster, but it'll be fine as long as you've got skill. 4.4.6 is the only other quest you might have a problem with, but again, with some skill, you'll be fine. In all honesty, that AA will shred through all of this. Really jealous of him.