Hello

After reading some topics I usually come around to people mentioning some units that stand out among others of the same rank.
Based on that, overall, which are the best units per rank/star quantity?

Notes:
People tend to talk about Marigold on three star characters... I found her to be one of the worst units in my opinion, low damage output, and bad special attack.

On 4 star characters I like Cepha, Snowflake and Lilac to be pretty solid units. People like St. Paulia, she is ok, but i think that Snowflake outclasses her by having more attack and defense and the same special attack (her ability is a bit worse, but let's be honest, those small buffs from 4 stars are to small to matter).

5 star: I like Night Phlox a lot. How is the new reissue event girl? I am thinking in rushing to get her for her 1.2x battle skill ability.

6 star: I only have Christmas Rose (good character but weird design), but from helpers and stuff I am inclined to give the cake to Lycoris, Alpinia and Kerria, am I wrong?