Building a Team around Saffron is easy:
1. Saffron: Give her the provoke Ability and feed her as much dressblooms as possible.
2. Apricot or Habranthus: Both Girls negate Damage from enemies once. Usefull Ability for an Attrition based team.
3. Anemone or any other Girl who has Counter+Supercounter and also buffs Defense. Canola is also super solid after promotion.
4+5:The fourth and fifth girl are flex spots. There are so many Counter Girls available by this point it's hard to mess up cause if you follow the basics you will be fine.
Easter-Cactus is good for revive, Nightmaher has Counter+Evasion and Sneezeweed is solid. If you desperately want a Blue Counter Girl you are basically forced to use Viola (Yukata) or Ghost Weed cause to my knowledge they are the only Hit Counter Girls.
Also for OP 5* Unit who has the potential to become better than Saffron after Promotion: Pink (Miko).
But you already know this