Yes and that makes his other actions grooming, but it also disqualifies the actions I listed because he doesn't seem to be doing them for that purpose despite his overall goal. It isn't insanity in this case, his self questioning shows a thought process that doesn't involve expecting things to turn out differently than what is to be expected from the actions he took in the cases I mentioned, a result which in no way includes getting him closer to his overall goal.
As far as the giving him an opportunity, an obvious test from Yumi I saw from a mile away, she's not the type to go from being kissed against her will to actually letting the person who did it have her. She wasn't letting him potentially take a shot at her, she was testing whether he would make a move if she dropped her guard and he just so happened to pass to her admitted surprise.
Rin is still pretty firmly on the girls side of her sexuality, but yes, has shown signs like in a specific past event of hers, I don't remember the in game name, but I think it is dorm 45 in the code, where she actively kisses him at the end on the good homie route. However, she's currently dealing with Otoha, so she isn't open necessarily, at least not yet.
She does like him, this is apparent to the player and has been since the first Christmas event when she gifted that notebook. If she still fully hated him at that point, she would not have done so. However, even with this, she shows only hostility and neutrality depending on the situation. In the cases shown in your comment above, she's showing the latter, neutrality. Neutrality is not an indication to most people that someone likes another, even for someone as smart as Nodoka.
Yeah, Ami's a little girl, but she's also insane clinically speaking to the point where she would take what she wants given the right, or would that be wrong, circumstances and would eliminate any threat she became aware of. She shows blatant hostility when he brings other girls over without even knowing the intent behind bringing them, even ones she personally knows and has a good relationship with otherwise, and let's not forget her actions toward Ayane and Maya, her best friends out of the entire cast. Yeah, he had a choice, a choice between letting what happened happen or being forced into what happened or worse, which is less an actual choice and more an illusion of a choice that was already decided for him. She's a devious little thing that will do whatever it takes to get her way, even if it means force. Also, you mentioned her backing off a bit, this is planned, she saw a threat to getting what she wants coming directly from Sensei himself and so she is biding her time. Make no mistake, she is not just backing down because he asked, she's doing it to avoid the consequences of not doing so, which includes potentially losing him entirely, a circumstance that must be avoided at all costs in her mind. That's how yanderes operate, they do anything and everything that is necessary to keep the relationship going.
Yeah, it matters who is worse when the characters are just doing bad things, but both of them did things that get the same general result, that's why it doesn't matter who is worse between these two. Both are going to end up doing some serious harm to another character at some point, that's what really matters and that's why it doesn't matter who is worse between two characters within criminal actions territory. The next part I agree on, both could be mass murderers, doesn't matter how many victims each one had, they still killed four or more as per the definition and even a single death at their hands is bad enough that they both deserve the same thing, jail or worse. No, Kirin and Yumi aren't worse than Nodoka, Nodoka committed sexual assault by making Yumi masturbate, Yumi is only guilty of bullying Futaba, who is very much still alive, so no murder at this point, and Kirin is guilty of blackmailing Ayane and Sensei. These are both not as severe as Nodoka's sexual assault of Yumi.
