The Jocks didn't post it. Just because Dawe is antagonising the DIKs by rubbing it in their face doesn't mean they're guilty, it just means he's being a douche and it's what anyone in that kind of rivalry situation would do.
Not always. Sometimes the hero of the story can hit a roadblock that causes important characters connected to them to walk away from them because they feel let down/betrayed/disgusted by something the protagonist either has done or is made to appear as though they have done. The story then moves on a few weeks or even months to where they are still not speaking/interacting with the other characters, but the next major story beat now occurs and it will lead down a path to re-forging the relationships they lost.
I'm not saying this will be what happens, or that it has to be, but it's something I could see as a possibility and one which I personally think would be interesting and engaging if done right.
But again, this still gets to the issue that certain things will happen that are outside the MC's control that end up affecting him directly and we've already seen that as well as being set up for it. Not every character has to abandon the MC if something were to happen that puts him in a bad spot, and they would certainly have plenty of time for redemption and recovery, just like the examples you gave, but if such a thing were to happen to them, it's not necessarily a bad thing.
Despite the things that have happened already, I feel like the MC has had a pretty easy go of it so far, but there are other things going on in the background that could derail this somewhat cushy life and stories where the protagonist suffers a major setback and then has to work their way back up and repair the damage are some of the most satisfying, even if they're hard to watch when you know the protagonist doesn't deserve what happens to them. In the context of a VN like this I feel like it could be even better because while the setback may be out of our control, the recovery is entirely within our control and could give players a real sense of triumph about the fact that they get to take part in undoing whatever happened to the MC.
Jill knows the MC dated Josy, but that's about it. None of the other LIs have any reason to suspect anything about each other, although that might change with this DnG game in ep 6. Bella certainly doesn't know about Sage, Maya, or Josy, Sage doesn't know about Jill, Maya, Josy, or Bella, Maya doesn't know about Sage or Bella but might know about Jill if Josy told her, and I guarantee none of them know about Riona, Camila, Sarah, Melanie, and Quinn if you had sex with any of them because they're a tight-knit group that's doing something they shouldn't, so they're not going to spread that around with people outside the group.
