I think a group of Others was introduced because a girl can break up with you because of infidelity. You stay alone and enter into a relationship with one of the girls of the Other group. But if, for example, you are on the way of a Chick and have not fucked anyone, then Zoey appears for this.
It seems to me that there will be infidelities, because one way or another any happy couple has a potential threat.
Sage is Jade or Quinn.
Jill is Zoey or Bella.
Bella is Jill and Zoey.
Maya and Josie are Zoey.
So if a girl leaves you, you can come back from a girl from Others and start a relationship. Many scenes can be repeated without creating unique scenes, this will facilitate development.