A relationship with an older woman, even a teacher, is not impossible or unrealistic, nor is a relationship with 2 girls at the same time or a relationship with someone who was in a lesbian relationship but either is, or realises they are, bi. You just lack the imagination to see it.
Granted, I cannot discern how exactly the relationships with Bella, Maya, and Josy will unfold or what the endgame will be, but I know for a fact that they will have endings, no matter what obstacles are in their way and that they will make perfect sense within the context of the game. It's a not a 1:1, 100% perfect depiction of the real world, so some things in the story might bend believability (like a drug and prostitution ring being run out of a sorority), but all LIs will have endings if you make the right choices and will work perfectly fine in the world DPC has created.