Step 1: Kill or dispel zombie to remove taunt
Step 2: Kill another sister twice to expend zombie's auto-revives (usually Ventress is the squishiest)
Step 3: Kill Daka
Step 4: Kill Ventress and Talzin (preferably in that order, but killing Talzin first is fine if it stops her from getting a turn)
Step 5: Kill the 4th and finally zombie
You may need to kill the zombie once after burning its auto-revives to nerf its speed and prevent it from taunting again. You also need to be careful if Talzin has her unique zeta, as it will give her extra turn meter several times while you're wearing them down.
AOEs are huge, as has already been mentioned. Bringing a healer to deal with Plague also helps a ton - you can't dispel Plague, but healing to full health removes it.