I just did last tier with g9 leia, han, R2, g8 Luke. Only an omega on R2 basic to help with stuns. Moved my arena mods over and still took 4-5 attempts to get the right RNG. I would say that is pretty close to a minimum required gear for the event. I was g8 on all toons, and had enough saved to move them up to g9 as needed. Spent about 15-20 tries right away and moved han up to 9, 15-20 more and moved leia up, another 15-20 and R2 went up. Didn't take as long once I got R2 up.
I did come very very close once when I had just sthan at 9, so maybe if I had some patience I could have done it with less gear invested.
