I have Heather in my helper squad and she's quite solid. She's basically hit type's Aloe and she gets a pretty respectable affection boost. Unfortunately I doubt either Heather or Aster will get a Bloomed form on Nutaku in our lifetimes. Oxalis... should. Gardenia is another one to look at if you want a hit type.
I have and like is Lagurus (Halloween) but her wikia entry looks like a downgrade of the Nutaku version? So she may be in for a nerf.