Josy and Maya will probably have many different outcomes, even if you part of their relationship. You probably will be able to keep it together, if you part of it, or chose one of them.
as for Bianca , She is not flirting with MC if you are not on Jill path. Yes she is cheated on, that is an universal thing, like when Chad breaking up with Sage. or Josy and Maya being in relationship etc. but there are mutually exclusive things just for specific paths. Like the Jill x Bella, if you on both path, and you pick Bella, Jill try to kiss you, and dont tear up the picture of MC , thats not happens in any other case, only if you play that specific way.
So yeah, events will play out regardless, but to be involved in it you will have to be in a specific path. and Bianca is one of it, I'm sure.