@UnstopableSteve
Bossk is great, Jango is great (though I don't have him), but definitely don't forget to invest in Dengar.
While it's possible to do it without him, and even with him you're going to need to restart a number of times, killing Chewie first is the optimal strategy. Dengar's unique preventing opponent Stealth allows you to target Chewie before wasting a lot of time against r2.
It may sometimes be necessary to kill Lando even before Chewie if Lando gets his AoE rolling early, but again, r2 almost always assigns the passive-tank roll to itself, so Lando's going to have stealth too without Dengar.
I've got 5x g12 BH, including Bossk, Boba, CadBane, Greedo & Zam. My thermal detonator team works really well most of the time, and I had avoided spending on Dengar so I could keep the gear flowing from the Guild Store.
After the last event (when my BH were much weaker, but still deadly with the Greedo/Zam combo) when I failed hard, I decided to get Dengar. he's at 88/100 right now b/c I didn't expect the event to come back quite so quickly, but I'll still be fine. I've been setting aside gear for about 5 days now, and the only thing I'm really lacking is Carbantis, so Dengar's gear level is going up as fast as I can get them.
In the meantime, I played the event more than 20 times with the g12 BH squad I've got, experimenting with both Boba and Bossk leads. I've never come close to beating it. Best run killed Chewie, Lando & Rolo (I would have liked to get RH, but I needed a guaranteed Boba revive b/c he was so low, so I killed ROLO first). But by that point it was Boba standing alone, and I got taken down pretty easily between RH's stun and R2's stun + the damage from RH's basic.
I know some people have played it many more times, and I'm sure I could break through, but since i'll have Dengar in a day or two I've suspended my efforts to try when it's easier.
I'll report back on how much of a difference it makes and ultimately which character got swapped out.