If you have Sun Fac geared you can use him as a tank instead of GK and move GK to the Jedi team. He removes taunt on basic and counters. If he's not dazed of course, which tends to happen unfortunately.
I do Church of Nute instead of the Ackbar team and I've found through trial and error my best scores are with L3 in the tank spot. Once she gets up Mk II she doubles her defense, and with Thrawn feeding her protection and her constant taunting (which doesn't rely on crits and rarely is on cooldown) she can often get everyone to enrage (other than my G6 Nute, who doesn't matter other than his leader ability).