This is definitely one of the more annoying feats to achieve, and I agree that getting 30 stuns without killing everyone makes the event very tedious and frustrating. My thought process for achieving this feat was to get as many aoe/stuns all enemies characters as possible, then fill with the rest of the slots with high stun proc rate characters. I used Emperor Palpatine, Royal Guard, Dooku, Han Solo, and JKLS. I did achieve TierX on my first attempt with this lineup. However, I don’t think we really should have to mesh random characters together to just to get a check in the box feat,