Can anyone beat this?

I beat it. Takes RNG being on your side, but the only hard part is grievous. Beat it with GK, both yodas, zarriss and ezra. Basically use wave 3 to recharge cooldowns, health, protection and get in there with full TM on GM. Then use every big hitting attack you have on grievous. You will probably get death marked, but it should hit GK and you should be able to dispell it before he actually dies, and then heal back up. When grievous is dead, the rest is a cakewalk.

The remainder of the event is almost insultingly easy after this.