Streptocarpus + 1 turn negate is nice idea, but that would take a whole 2 team slots, and I don't think I want to dedicate so much just for 2x skill act. I want to focus on crit + react + skill act., something along those lines, with react being 1st priority, then packing as much crit act., and skill act. as possible. A rough draft...:

Dendrobium: 100% 1st turn react (albeit no crit or skill act. for team, but I feel like it's time I get her for her voice...) ; +25% ATK team
Cactus: That continuous 60% react, one of the best (if not THE best) in game of its kind ; +15% Crit Rate, +50% Crit Dmg., +22% ATK team
Rainbow Rose: 50% React, insane self crit. buffs, +28% ATK, 1.2x skill act
Ume (Maybe?): Crit Rate +30%, Crit Dmg +55%, ATK +22%, Skill Act. 1.2x
???
(FINE...) IF I really have to add Christmas Rose (her effects are quite nice, not her design IMO): +20% Crit act/Dmg., +35-55% ATK, +1.28-1.36x Skill Act

Counting only team boosts, this can achieve max. 75% crit rate, +140% Crit dmg., +150%-ish ATK, +1.76x skill act., if I did math right. Maybe okay for a draft team?

Other potentials:
T. Stewertia (christmas)
H. Peony
Anemone
Wheat
Pgymy Water Lily
...and more I'm sure I missed

Curious as to what you guys think...?
(p.s. really wish there was some kind of FKG dmg. calc., or simulator, that would be awesome)