Sorry to ask this but there were scenes involving the other sisters, or the coffee barista, or the other schoolmates, etc.?
In fact the only ones who mentioned in the story section ever were lexie and skyler. I could be wrong maybe I'm missing something?
Those I thought also were the only ones who had interest locations. For example if you look at vani (the barista) in the social tab it says to raise her stats/values. I never saw any way to talk to her, lena, the other classmate, the principal or the teacher. Ella, Nati, and Mom you could talk to them but if there was content for them I have no idea how you were to access it.
I assumed slums was just a placeholder that never got implemented.