This game does not have a harem feel to it. I mean normally a harem game would have Marylin also fall in love with you, with you and the nurse also getting into a relationship (Plus the MC's mom for good measure) and then all of them lives happily ever after. I have come to realize, after a couple of good games, that I do not really like harem endings. It takes all the realism away for me.
I prefer games where you have sex with all the girls (minus the MC's mom in this game) during the playthrough, but eventually you end up with just one girl (Cheating and side-girls excluded) . To me that is more grounded in real life.
Back to Chloe and Mom...I just don't see it. Chloe was already devastated when she thought she caught them.
Maybe, possible... I don't know.
Also the MC clearly does not enjoy sex with Chloe that much. So the harem would consist of unequal love or lust. The current dynamic is that the MC is totally smitten with Niccole, Chloe is for convenience and Marylin is friend with benefits. in terms of passion I would put down the MC commitment to 80% Nichole, 10% Chloe and 10% Marylin. I don't see Chloe excepting 10%. Marylin could go for it, since Marylin only have eyes for Nichole, and a harem could be her only way to achieve that. The dev would really need to be good to be able to pull it off, otherwise the game would fall flat.
Off topic a bit:-
So to conclude, I don't exclude the possibility of a mini-harem ending, but I don't see it at this stage. The dev would need to be extremely good to pull it of for me. Seeing how he well he did the mom corruption (Close to the best I have played on this site), he has the talent, but maybe that is not what he is going for.