>>542868470
Nonomi and Iori will carry you through early yellow content such as yellow missions and the commissions. Muchuki is your go-to girl for red content, it looks like. You might think she's only good for AOE, but she does respectable damage to single targets as well, so long as you aim your bombs right. gPina will probably help you some early on but she's pretty niche desu, I'd avoid investing too much into her.
Cheese is kind of your only blue girl but I found as a newsensei that she fell off rather quickly, she always died very fast. Momiji will be of some help in blue content as well. 3 months into the game, I hardly use either girl. Make sure go into the event recap menu and read whichever event gives you Track Hasumi. They give you enough resources to (almost) completely max out her star level.

Yuuka and Tsubaki are some of the best tanks in the game. Serina is a cheap healer, she is your best friend.
Early game, you want AOE damage so you can blitz through the missions as fast as you can for cafe upgrades. Upgrading your cafe allows you to store more AP in your cafe before filling up, and will let your cafe regen AP at a faster rate.