Evening Primrose because shes given to all new players, Cherry and Sakura I guess because of their abilities? Art style is subjective to each person so I dont really know
There are many girls under "2nd evolution available" but none of them can bloom yet (except Sakura, Cherry and Evening Primrose), so I don't have any idea which specific mats should I stock up.
2nd evolution requires a total of 5 mats: 2 Birds matching the unit type (slice/hit/pierce/magic), 2 Petals matching the unit's nationality and an elixir matching the unit's rarity.
Birds can be purchased with Sun Crystals @330 each.
Petals can be purchased with Life Crystals @150 each (they can supposedly drop elsewhere but I haven't seen that happen yet).
Elixirs need to be farmed from the Special Mission.
And here I thought you need to max 2nd affection first in order to 2nd evolve.
Have they added the character quests and h-scenes associated with the blooms?