So, after fiddling around for two weeks, i think i feel comfortable now with:
Chi-Chi: Rapana Whelk, Silkbead Snail, Scooter the Snail
Acidic Goo whenever he isn't debuffed, Dive whenever his Dodge is off cooldown (pass otherwise), Ooze Touch to fill. Repeat.
You might get away with another common snail instead of Scooter.
Xu-Fu: Tiny Twister, Lil' Bling, Darkmoon Tonk
Twister casts Call Lightning, Switch to Bling, Make It Rain, Inflation until Bling dies. Darkmoon Tonk: Shock and Awe, Ion Cannon.
Yu'La: Clock'Em, Bonkers (backup), A cold potato in my third slot
Dodge Lift-Off, Jab to Fill. Should Clock'Em die for any reason, do the same with Flipps. You may even use Tornado Punch whenever it is off cooldown.
Zao: Tiny Twister, Ikky, and anything hard-hitting to finish in case of Ikky death.
(Heal Twister before combat - Even though he shouldn't take damage, better be safe than sorry.) Twister starts with Bash to cancel Zao's charge, then Call Lightning. Switch to Ikky, Black Claw, Flock. This should be enough. If Ikky dies, use something like Darkmoon Tonk's Ion Cannon to finish.