I think it wont happen, the harem that will surely to happen will be sky and gwen or maybe moon and lily.
Maybe. but we can be hopeful lol and tbh imo those 2 are the best characters in the game and should definitely have a future together with the mc.
Also irl harem is unrealistic even if all party is happy eventually you would get tired of it or feel neglected and it is unhealthy and not to mention laws to prevent that.
But if such intertwined past like those 2 and the mc exist even if irl. I would bet that 3 of them do end up together. Hopefully Niichan decides to go up that path. Nonetheless love the game.