I managed to six star R2D2 with the following: Tarkin (six stars), Vader(7stars), TFP(7 stars), RG (7stars) and Snowtrooper (six stars). Took me several turns to beat it with this squad. That team i...
Barring a Zeta Vader leader, probably having Palpatine as leader would be the easiest way to beat the event. If that's the case, then well done getting thru the event without him.