There is no definitive closing off of any of the paths due to these decisions.
As I said, the only one that might be is Bella, but that's dependent on a player being given the choice to ask for Bella's help or not, and if they choose not to then the end-of-episode summary says something about how the MC doesn't think they should pursue things further. Even then, he might not want to but she might, and the MC could still do it. But if a player is on both the Bella path and M&J path, having Bella come to help doesn't have an impact on the M&J path, nor does the flirting with Becky at the start of the episode. Yes, it results in the loss of 1RP for each of them, but that's barely anything.
As for Jill and Sage, if you're on both paths, choosing either one doesn't end their paths either, it just results in Sage being a bit pissed at the MC for not showing up and Jill being upset at not being able to go on this date. But there's nothing that suggests either path is definitively closed, not even what happens on the Jill date because afterwards, if the MC is pursuing Sage and others, he ponders what he's going to do about them, so it's still very much open in terms of how this will go and isn't over yet.
