This is true, Ayane was one that had been into him since the beginning of gameplay (she was practically willing to give him a little something in the bathroom if you get what I'm saying. this is referencing the original opening scenes), so hers made sense to come up as early as it did. I could also see Sara, she was in a situation that seemed to push her in that direction. Tsubasa doesn't seem as open a character, doesn't seem to have something pushing her in that direction in terms of situations or outside forces, and she didn't essentially default to having feelings for him, not even outside of love, so I think she would take a bit longer. Remember Niki, who Sensei actually dated. She does have a scene, but it took time with her.
I'm not so sure wizard content won't be soon, but I am sure they aren't going to get dropped into the middle of a threesome for their first scene, it's never been something like that for the first. Story wise, assuming she even finds out and against all possible odds approves, I don't think Chika would allow it. Tsubasa might be open enough to allow such a thing with Tsukasa, though. I think Chika would want Chinami to have her first solo with a loved one like she did if she approved at all.
As it is now, with the missed events, I do believe all other choices to be there to throw the player off in cases where they haven't been paying attention and have a preference toward one of them. However, they could be setup for the future as I said before, both setting up for missed events for 'taking things too fast with the girls' and setting up for the potential groupings we may see later.
Tsubasa does have something pushing her towards being with Sensei though. Fun, experience, and depravity, plus the whole seeing him as an equal, trying to help her daughter sleep with him, and implying she'd make "
arrangements" if he told her that Chika and Touka couldn't satisfy him, seems to imply she's ready whenever. Niki is more of a special case, since Sensei put off fucking her, potentially since they were teens (possibly because of Sekai). It's similar to how he refused to fuck Imani, Molly, Noriko, and optionally Ami, Haruka, Maki, and Sara. They aren't really the problem. He is. They'd be fucked if he pushed for it. The characters are ready, the protagonist just isn't apparently. I don't think Sensei has a reason to put off Tsubasa considering he can suggest her for a threesome.
Yumi, Rin, and Chinami on the other hand? Yeah, I don't see them being ready for sex themselves. I can see Yumi and Rin being convinced to be there by Chika though. Same with Tsubasa. I wouldn't be surprised if Tsubasa accepts it just to feel young and be "one of the girls", albeit she does seem worried about her husband finding out so I guess we'll see what happens. Onsen trip 2.0?
Maki's first sex scene was a threesome technically. Nodoka showed up to watch Futaba and Kirin, and could blow Sensei in front of Yumi, on top of having Yumi masturbate in front of them. Technically those aren't really threesomes, but it does show a character can show up in a sexual scene before they get their specific own. Noriko technically could watch Ami blow Sensei before she gets her own lust event. Tsubasa also was apart of Chika's 'Mating Season' scene technically. I wouldn't write off a "Threesome" just being something like Yumi or Rin watching Chika and Sensei. (Not really into the Wizard content so, imma abstain from this point)
Possibly. As far as I can tell, the most damning choices seem to be not fucking Ami or Sara. Quite a bit of the lore and presumably important stuff is missed.
