9thcrux has already said several times that there will be no harem ending. BionicMan [FR] only indicates something that has already been said:
I'm OK with no harem ending, in fact this game has way too many LI, and like half of them are completely uninteresting while others are great which make the worst ones really annoying to waste time on.
But there is one thing the game right now is very harem oriented, the whole Tiffany, Joan, Daria and even Emily seem like very obviously leading to an harem, the girls are confortable and really enjoy each other company, they know that each of them are interested in the MC and seem pretty OK with it.
Tiffany does say somethings but an actual jealous or possessive girl wouldn't be bringing these other girls that are so clearly interested in the MC and putting them in sexy PJs, etc. Instead she would be shooting daggers from her eyes and keeping them away from the MC as much as possible.
Honestly at this point with how the story is progressing I don't see how it could NOT be an harem ending.