Before we can really discuss who get endings we need to talk about the mechanics of the game's end. Currently I'm expecting it to be a montage and an epilogue sex scene. The game will call all the significant decisions and based on them different things are included in the ending montage and an epilogue scene is unlocked. If the final episode has no other scenes but the epilogues we might get a total of 20 ending scenes, but that might be optimistic. And the main girls might get multiple scenes. Josy and Maya I'd expect to get their own endings and a throuple ending and to balance it out Bella, Jill and Sage should be involved in more than one scene as well.
I'll go with the assumption that the full count of scenes is main girl scenes + 10 side girl scenes. Note that these will be fully animated scenes and practically any girl can have content in the montage. Also the scene might not be a happy future kind of ending, but simply something that happened in MC's remaining years of college. So who gets an actual scene?
100% certain: Zoey, Quinn, Lily, Riona, Nicole and Nora. Some of you might not consider these as equally likely, but I'm working from the assumption of a total 10 scenes and the idea of any of these six not having her own ending among that many is laughable. But if you want to discuss which of them is most likely should there be less than 10 side girl endings I did put them in the order of their likelihood starting from the most certain.
Camila is also very likely, but I don't see her as an absolute. Similarly I can see Mel and Sarah having a shared ending as highly likely, but their solos are very unlikely.
I could see Jade having her own ending, but I'm not nearly as certain of that. A secret student teacher relationship that ends when MC graduates. It could also be a shared ending with Cathy. Or they could each have their own endings but I consider Cathy's solo ending much less likely.
Sally is tricky to judge. On the one hand hardly anything has happened with her, but on the other hand she has had a role in the story for a very long time. I wouldn't rule it out but it depends heavily on what happens in the remaining episodes.
Heather could happen, but there would have to be some serious build up and that is by no means certain. There is a chance that her purpose in the story is to be a trap and pursuing her will only bring ruin.
I have no idea where Cindy's story is going. At all. Something is there, but what?
I don't see any other character as having a solo scene, but there could be a sort of "the most amazing thing that happened to me" kind of multisome scene for a manwhore game either with dorm girls such as Tara, Tiffani and Christie or with the Pink Rose girls.