Finally!

They were all level 80 except chopper, he was level 75.

Ok I'll try switching mods, see if it pans out

I found strategy and getting a sense of the timing to be the key myself. Being able to anticipate when fracture was coming was a huge turning point. Forcing him to fracture Chopper is a big old load off.

Tried it for days, then right after I beat it with my team, I helped some friends beat it with lesser teams (I beat it for them).

I had Chopper t9, the rest were t8. Use Ezra to wipe the taunt, not chopper, he must taunt to draw Thrawn's fracture. Kanaan must taunt to draw the rest of the damage. Use his and Zeb's protection abilitites on whichever tank is actively taunting. Use Hera's backup plan on whoever is fractured. Use Zeb's special to take one buff off, and a buff wipe for the other. Death Troopers first. Stormtrooper Commanders next. Leave no buff up in this match. Taking them all down is first priority. Hera always calls Ezra to assist. Ezra always calls Hera. Thrawn dies last.

I bet I could beat it within 5 tries with anybody's all G8 team at this point.