I forgot Night Phlox had evade.

Oncidium is fully equipped so she can survive easier.

Level 80 boss, not level 90.

The advantage on Kerria, Waterlily and Oncidium is that all lvl 80 Iron Scorpions are slice type, so their heal benefits from the type bonus.

Unfortunately, lvl 90 are hit type.
We'll see on phase 2.

A Sensitive Plant/Acacia/New Year's Ivy/Halloween Herb Pony/Night Phlox setup could work for the level 80s. There'd only be -55% pest power but with two slice Knights in the party Sensitive Plant's base ability would guarantee that all five Knights are hitting the slice weakness.

Nothing to be done about the level 90s though since there are no Knights that increase damage dealt to hit types yet.

Well, there it goes...