NOTE: this post might contain some ultra light meta spoilers. In general shouldn't really affect the experience.
(We all know the golden rule, this serialized echi manga is canon while the Hentai (H) version is not.)
I've already started reading it a while ago, but as I was rereading this and tried to look to the Hentai version for differences, I was glad that this basically invalidates/trumps the hentai version and changed the girls from dick loving maniacs to simply Imaizumi loving maniacs. In fact, I was the author seems to have backed off that part so much that now these 3 girls seem to have been virgins before fucking Imaizumi.
This can be seen from Yukina thinking about whether she fell in love with him because she had sex with him (this is in chapter 3 I think), which she wouldn't have to question if she had done it already. Then, as for Hamasaki, her reason for getting involved with him in this is shown to be because he doesn't judge her to be a slut (or someone who would fuck anyone, etc.) just because of her being a Gyaru and a model, and since Yukina is so different from the Hentai version, it's safe to assume she is as well. Finally, for Ruri, since both of her friends are now normal, NOTobsessed-with-dick people (and are even virgins), so must be Ruri.
Clearly, in this version (THE canon version) they're with Imaizumi because of himself and actually care about him. They're totally different from the non-Canon H versions (probably that version required those personalities because of its medium and intended audience.
Additionally, even upto Chapter 25, there hasn't been any proof or even suggestion otherwise (in fact, not even about any general romantic relationships prior to this). In fact, I doubt there'd ever be any.
I do think that Lisa probably might not be that different from her H version, but I haven't really read that far into the H version anyway so I can't be sure.
P.S. I don't know why I wrote this. Perhaps I just wanted to waste time.