Since the game isnt fully complete, we may see the option to instead have Ellis as a heroine around rank 4-5 once (and if) the game is completed and finalized. Iirc, most of the NTR that doesnt include losing to the bosses (other than the penalty points) happens after those ranks, so it would be feasible to assume that would be around the time you would make your choice of heroine. Much as the unfinished product was vexing and all of us are quite let down by the fact, Im still hoping that we will eventually see an update for it again.