ice them and don't use all out attack. learn there order if a tank come back up right after you ice it and before any of your team attacks. let your team attack that tank. Just keep doing that for each tank.
I think I might be the most sigged person in the FFXSB right now... -noneofyourbusiness
dont set mitsuru to knockdown. since fuuka's scan doesnt show their weakness, i doubt mitsuru will use bufu skills. instead, fuse a persona, any persona, with bufu skills, and boost and or amp too if you want. then just knockem down, wait till they get up, then knockem down a few more times, finishing with an all out attack. 2 bufus and 2 a-o-as should be enough to take them out. i got through them without anyone getting hit. took about 3 minutes.