I just unlocked 6* this morning without ether Bossk or Dengar, but the gear requirement is pretty steep (G12 Boba, G11 Cad/Greedo, G10.5 IG-88 and a poor G8 Zam cannon fodder, all with arena mods and and 70+ potency as a minimum). This seems to be roughly in line with the "recommended gear" (G11+), maybe slightly below it which is why it required a healthy dose of restarts and near-perfect RNG to be successful. So, I'd expect that you'll probably need G10 if you plan on throwing "any old BH" in T5, though you could be succesful if you have a lineup that is better for taking out this event (Dengar and/or Bossk). I'd say with proper RNG, you stand a decent chance be able to beat the 5* with G8 Bossk (L), Dengar, Boba, Greedo and Cad. The farther you get from that lineup the higher your gear requirements will be. Also, if you've got someone other than Zam (like IG-88) I'd recommend gearing them first since she is probably the worst in this event (basic is weak without detonators and all her specials feed enemy TM). You'll need to rely on TMR and hi damage to win rather than debuffs (detonators). If she's all you got, then just mod her for health/protection and potency (if you have a boba lead) to increase everyone else's health until she dies. Don't worry about speed for her.
