First off > Welcome Back Game ! Here take this obligatory mofu to keep you company while studying:

:3

Ghost > yeah same here. I tried running 4 games (2x FKG -Nut/DMM, and GS and one more), then dropped to 3 (FKG, GS), and eventually dropped Nutaku FKG as DMM is superior to it in every aspect other then paid gachas, even while I dont understand anything written (I do catch up a little here and there on the spoken JP front though.) but still its better than the other one.

But I could feel the burn after a while, is what I wanted to say. It felt like a bloody chore logging in every day, doing the same stuff, and eventually it made me not want to keep playing these browser games.

Then they closed GS, and eventually I left Nutaku. Progressed far enough of DMM that even if I skip a day or two of loging in (didnt happen though lol), I am still good to go, and eventually GS will come back hopefully better then ever.
So yeah, if you have an actual Real Life, and you want to play browser games, 2 seem about the right amount to not get burnt out fast. At least for me.

Durrem > You have some nice girls in there to choose from... haah the amount of Manyus... I am so jelly of ya !
Anyway you have two universally great girls in there: Appricot and Tritonia.
Both have skill act, and both come with the very rare, and super precious Barrier skill.
Appricot is slightly better then Trit (if Trit had better % on her "per type" buff she would be amazing, but as it is, the actual value is less than some bacic buff types other girls come with, without that stupid gimmick. 9% would be amazing, and 10% would be insane, but ah well... hope they buff her as I want to pick her up as well), and both of them are of great value in any type of team > but work best for high offensive teams like Critical or Boss Killers.

The reason being > sure you loose a bit of damage from swapping of the DMG girls for them, but the fact that because of the Barrier your team cane survive 1 round with the Super OP bosses who one shot anything or the ones who go First and twice, which double your damage even with the loss of one damage girl. After all its better to be able to fight in 2 turns and deal slightly less damage each, but more in total, than deal slightly more damage but fighting only once.

So yeah, Apricot or Tritonia is who I would go with.