They do, and they seem interested.

"Master Izuku wants Mina for his harem!" Ochaco said quickly and excitedly. When Izuku gave her a flat look, she giggled sheepishly. "Sorry Master, couldn't quite hold it in!"

"...as blunt as that was, that is basically the point, yes, though there's way more to it than that," Izuku gave a sigh of fond exasperation. "For one thing, this harem is strictly voluntary, and while Ochaco opted to be my sex ****, that's not the only available dynamic."

"...and why am I here?" Kirishima asked, raising a hand a bit awkwardly. "I think I heard Yaoyorozu mention that you weren't bi, hence why I'm clothed..."

"We brought you here because if you and Mina have any kind of feelings for each other, well, we don't want to get in the way of those," Izuku replied. The two glanced at each other. With their inhibitions gone for the moment, they couldn't deny, they were indeed interested in pursuing a relationship.

"...and if we do? Does that mean I'm no longer invited?" Mina inquired cautiously, gazing at Momo. The idea of sexy magic being used to enhance her sex life was oh so tantalizing...

"No, not exactly. See, we're not exactly... exclusive," Ochaco grinned. "After all, Momo, Yumi and I are sharing Master, so he really doesn't consider it fair to not share us in turn. In short, we're perfectly allowed to date, or even just have flings outside the harem. Though I have yet to do so."

"...sounds a bit more like a polycule than a harem at that point," Kirishima noted, before pausing. "Wait, who's Yumi?"

"Oh, right, you probably know her better as Nomu," Izuku remarked. "Momo gave her a mind, several actually, of her own."

"Oh, makes sense. Of course you'd take the opportunity to make yourself a nice sex toy out of her if there was no mind to supress!" Mina giggled.

"...so, what?" Kirishima asked. "You want Mina in your little group, but allowed to have me as a side piece or something like that?"

"More likely the other way around actually," Izuku stated. "Since you two are taking the opportunity to confront your feelings with each other, this can be the catalyst for you to get together, with Mina being part of the harem on the side... and you being a "side piece" for other girls in my harem in the process, if they want occasional fun with you. Or we can just disregard Mina being part of the harem entirely, and you two can get together without issue, and maintain monogomy with each other, if that's genuinely what you prefer. Of course, regardless of whatever path you choose, I will be having Momo place a spell on you guys to ensure you can't spread this around. Not that I think you would, but obviously, I am not taking chances. In truth, I was initially planning on wiping Ochaco's memory if she turned me down, but after thinking of a non disclosure spell instead when Jiro found out about this, I find I prefer that route instead. At least this way, I can share the secret with others without risk. I'm even willing to have Momo grant a few wishes between you both, within reason of course, even if Mina turns down joining."

"Jiro knows, huh?" Mina asked. "Let me guess, she overheard something, and you forgot she had superhearing?"

"...actually, yes. Specifically, she overheard us upgrading Hagakure's Quirk, and got curious when she saw what she overheard actually happen. Thankfully, she asked us directly about it instead of running off to tell someone we would have preferred not knowing... that could have gone way worse," Izuku said sheepishly.

"Heh, I thought her ability to turn visible came out of nowhere," Kirishima snorted, shaking his head. "...mind if Mina and I have a few minutes to discuss this in private?"

"Of course, go ahead. This is all your call, after all," Izuku nodded, and Momo spawned a cabin for them to go into, having control over the dreamscape she crafted. Mina and Kirishima went in, and Izuku sat next to Ochaco to wait.