It's really a matter of which gold is your waifu or which golds you frequently use, or which golds you would REALLY want to bring on your Whaleship for their stage buffs.

First one, only you can answer.
Second one, this reply I posted to a similar question just over a day ago might be helpful. But, look through your squads and decide which units you feel are really important.
Third one would be Chocolate Cosmos, Lantana, Strawberry Candle or one of the following:
Convallaria, Tree Peony, Rose, German Iris or Allium. Maybe not in one of your front-squads, but starting with 20%-30% on your Solar Beam is still very useful on the whalemaps, so might as well make the best of those units.

Pretty much wut Drop said

For me, Chocolate Cosmos - waifu and chocolate nodes

Lavender - strongest loli in my army

Peach - strongest 5* (big boobs) in my army w/o ampy

Cymbidium is worth it if you have her, her 2x skill 1st turn is beastly but her base stats are lacking, also Megane Waifu!

The following is a personal recommendation, of course, there are other good girls.

The evil ninja Loli is one of them.：p

Cymbidium for me too. This girl is just one on the best golds if not THE best gold. Her 2x skill for everyone turn 1 is unique and even rainbows don't have a such skill activation ability.

Originally Posted by fghk0

The following is a personal recommendation, of course, there are other good girls.

The evil ninja Loli is one of them.：p

OMG can't believe I forgot about HyperLoli, she would be so good with 2nd affection since you can give her 4 def boosting items and she's a counter girl.

One of the best counter will be Mountain Lily. She gain counter with bloomed form + her 20% DEF + 4 equip slot. She can deal over 10k counter damage. Hyperloli is good too right now but less good when blooming will come.

Originally Posted by maotd

One of the best counter will be Mountain Lily. She gain counter with bloomed form + her 20% DEF + 4 equip slot. She can deal over 10k counter damage. Hyperloli is good too right now but less good when blooming will come.

I think she still as good as ever, with beastly active skill that surpass any hit all gacha 5 star girls. (2x on 3 vs 1.7x on 3, activation rate is 34% vs 32% at lv.5) Good boost in raid boss battle and ability to counter. Although 2x def counter is not really high since her def is average at most. But with 4 equipments it is more than enough.

So Hyperloli can be treat as counter or damaging unit depends on equipments. Very versatile and exceptionally good for event girl.