So... I know you've tried all kinds of things, and I'm trying to be helpful. I'm not assuming you haven't tried everything so much as I'm just double-checking:
1. Have you tried adding ROLO's zeta? I have it and the TM gain can be impressive, which allows you to run slower mods than you otherwise would so you can focus on boosting other stats.
2. Vader heals. it's what he does. Have you tried focussing on the side toons? You can kill them, and remember ROLO's special does 10 hits distributed randomly among all targets. And that's fine when there are 6 targets. They can all take it unless there is really bad RNG. But if you don't focus on Vader at first, and just let the AoE take down his Protection while you're killing the side toons, you can end up with Vader alone or Vader + 1 or 2 and then it doesn't take spectacular RNG to get a large number of those hits to all focus on Vader. With Threepio you can reduce cooldowns quickly and with a little luck be getting the AoE off frequently.
3. You don't have to survive all this. CHan will bring ROLO back. So CHan is the one you can't lose. But you can give yourself longer life with Crit Avoid primaries. And slowing down to get your CA primary can be compensated for with her zeta (as I alluded to above).
Again, I'm not assuming anything. Maybe you've tried all that. But you didn't write much detail about how things failed. So I throw this out for you to use or discard -- no expectations that this is actually helpful, but if it is that's great.
But as a last thing, people are streaming pretty constantly on 50 Shards right now (because the Reva and KAM missions are both active). Although TB battles are our big focus, we've streamed T2 with other folks before and would be happy to have you stream over on our server. We'll watch and shut up just so you have someone to pat you on the back when you need it, or if you want ideas you can just pause your next move and ask opinions or whatever. People are really helpful there, and you should know that option is always open to you.