The weaklings team defeated Kaguya, the Chrysomallos and the Golem.
When I decided to make Kogasa a tank, it worked well, since every attack the Chrysomallos landed on her it did 0 or 1 point of damage.
Kaguya... Parsee...
The golem was tough, (like if it wasn't before...) how lucky I am that Wriggle poisoned it, Minoriko did 150+ damage, Rumia wasn't hit, and Hina could debuff that freaking thing (she still died though).
EDIT: There goes Alaya Vijnana (or whatever you call it), Meiling, Cirno, Kogasa and Parsee did a great team here, Meiling spamming Moutain Breaker, Cirno and Kogasa using their cold spells, and Kogasa and Parsee inflicting terror, you're doomed.
EDIT2: Komachi, not so hard, many damage dealers, Yuugi, Wriggle, Minoriko (1420!), Alice, Chen, Mystia, Hina (surprisingly for me) and Kogasa. All of them did a great job to easily finish Komachi. But, she owned Chen, Alice, Wriggle and Mystia in the way...