This is basically a harem game. The MC isn’t special at all—he’s just an ordinary guy, even working as an intern. He doesn’t have a big dick like Jeremy, he isn’t handsome like Axel, and his family isn’t wealthy like Perry’s. He’s not even better than dumb Robert. Yet somehow, with just a few flirty lines, he can easily get the other characters into bed.
i think unlike most harem games this game portraits quite well why each possible love interest is into ian (except alison, we are just told she had feelings prior to the start of the game). it's not unrealistic things like "he protected a kitty that day and i'm in love with him ever since."
most of the qualities you listed are shallow and aren't even playing a role in those women's interst.
cherry isn't seeking a shallow relationship at all, if that were the case she would never go for perry. she wants to connect with someone who is interested in the same things she is. ian fits the bill.
emma goes with the flow. she doesn't want to get committed on her own accord, but isn't fully against it. neither jeremy nor perry are really people who are dominant enough to decide the flow for her. people like axel would probably, but he isn't her type at all. ian can be.
minerva is sexually and emotionally frustrated. she failed being the wife and mother she wished to be and found holly to be malleable enough to substitute as her daughter. now ian comes and seemingly is a bad influence for her "daughter". she unloads her entire frustration on him and you can basically decide if it's going to be emotional or sexual.
holly is severly insecure and therefore admires both lena and ian, as they take decisions in their lives (being protagonist and all). of course the go to action is be interested in the opposite sex, which means ian in that case. (only later she realizes lena is also an option.)
cindy is fearing to miss out. she seeks excitement and thrill. her narcistic tendency leads her to become a model. axel is obviously everything she wanted, but even she knows how dangerous this game is. ian poses similiar excitement, as he knowledgeable about what she desires to be and being the forbidden friend of her boyfriend. though ian isn't threatening at all.
louise has committment issues. she wants to feel special. she can basically be swooned by every confident guy, which is the only reason jeremy was able to date her. with all the bad romance stuff she is reading, a talented writer like ian can make her head over heels any day.
but honestly that all doesn't even play a role in what makes a harem game a harem game.
half of this game is a male protagonist game. since it's not a kinetic novel of course this will have lots of possible love interests for the MMC. by the definitions you gave, every male protagonist game would be also a harem game!
we should rather look at the basics. one very basic rule is what actually a harem is. and a harem is relationship dynamic of 1 guy with at least 3 girls being exclusive/faithful to that 1 guy (with switched genders this would be a reverse harem).
this game already fails at that very basic and most likely first rule.
ergo it's not a harem game.
doesn't matter if it feels as one, or comes off as one, or any other definitions you can come up with: it cannot be a harem game if a harem never forms.