I used Old Ben, Fulcrum Ahsoka, Ezra, R2-D2, and Chirrut for it. It took a while to get through them all, but lost Old Ben because out of nowhere, the Emperor one-shot him, but everyone else survived. At the start of the round, I used Chirrut's cleanse ability to raise tenacity. That helped stop the stuns and kept Old Ben on taunt and just targeted the Emp the whole time.
It took a bit of work, but I did get through it. Once the Emp went down it was easy, just lengthy from all the stuns and buffing the RG's were doing.