No I disagree with you there about the MC knowing she was off limits. Josy did everything she could to encourage him. He tried to walk away. She's the one who kept drawing him back. The goodbye not farewell, the 'I'm running away' story, even in the scene after her Father's visit the 'I thought you'd fight harder' crap.
I just did a reply to Felice's post where I said I wanted to see her grow up some, but there's no doubt in my mind that Josy used the MC as an emotional crutch and then dropped him the second she got her Maya back. That's something she'd have to atone for before I'd ever consider her even a friend again.
With respect, I think you're reading things into her words and actions that are not there. Josy didn't drop the MC until AFTER he stormed out on her.
Josy asked the MC to meet her in the bathroom, and the MC immediately implied she lied to him about her "boyfriend." In response, she said she wanted to explain when she got here and that it shouldn't make any difference if her SO was a boy or a girl. It's only when the MC insists she should have told him all the specific details (including some rather private ones) that she snaps at him. And even after that exchange, her ultimate response is still "What are
we going to do...?" [Emphasis mine.]
Clearly she still saw the MC as more than a crutch to be discarded at that point. In comparison, Josy is fairly testy with Maya until they laugh over the diarrhea shit joke, and she still hasn't gotten close enough to tell her about the MC by the time of the library scene. Also, Josy is still trying to patch things up with the MC after that. Whatever Josy said in anger, she clearly cared about him to some extent.
As doing everything she could to encourage the MC's advances, I again disagree. At best, Josy took half the chances. It was Josy called an end to the first date, and she repeatedly poured cold water on things by bringing up her relationship or her own feelings of guilt. On those occasions, it was
the MC who did everything he could to encourage her: begging her to stay on the line, letting him see her over the weekend, or saying she must be unhappy in her relationship while on the couch.
I'm certainly not exonerating Josy, but unlike
felicemastronzo, I do see the blame split rather equally here. To me, it seems like both Josy and MC liked each other enough that they did things in the heat of the moment that they later felt guilty about. When the whole situation exploded, they both trouble processing that and occasionally took it out on each other.
That's more or less what the game will eventually explain, and IMHO it fits well. YMMV of course, but I don't think there's any evidence to support an interpretation that Josy was deliberately using the MC.