I don't think there neeeeeeds to be all these reveals on the first episode, including because putting all those 3 in one go may be a little overwhelming, both from the dev and player POV.
I'm starting to suspect that all girls are "side quests".
As alluded on the prelude, this is the story of how MC found a new family and, right now, I'd bet this family is the DIKs and may or not include a wifey, depending on your playthrough. It's a bit telling that on ep2 if you say you don't wanna join Delta Iotta Kappa the game forces your hand, twice none the less; yet you can move away from all LIs and avoid all SG without any issue by the end of S1.
Ma-a-a-a-y-be this family could be Derek, Maya and Josy, since you're not given the option to tell'em to F-off, but this doesn't feel right for some reason I can't explain (besides the tile, that is).
If that's the case, the main focus of the game throughout coming seasons will be MC joining and bonding with the DIKs, that will be the railway on which the story moves. Bella's, Sage's, Jill's and others plot lines will be stations along this railway, they'll be sparse, far between and, depending on your choices, may be skipped entirely.
P.S.: this would also explain why Quinn is not a LI, despite her prominence in the story and "marketing". Her actions are so intermingled with the fraternities and, therefore, the main plot, that branching her story according to RP and others variables would be unfeasible.