You don't need much on tier 2. Put an accuracy mod on Kanan so he can put offense down. If you use Sabine over Ezra, you will have an extra stagger besides Zeb's, and with luck that can be triggered by Chopper's assist. If you play it right, he will only do the AoE once. Since he can't be stunned, instead of calling an assist with Hera, use her basic to expose. At g8, you may need to put protection up on Hera and Sabine, and maybe use Backup plan on Sabine.
I did t3 last time with just putting protection on a g8 Hera (my Sabine is 11; so not sure what her minimum would be). My Hera is g9 now, so that helps a ton. I actually put a defense set on her, and try to find mods for your weak characters with protection primaries if you need to.
If in doubt, just take your one or two weakest to g9, but as with everything, having sufficient speed will be best so you can defeat him before he does too much damage.
