It'd probably help if I made it clear how I believe Quinn's 'path' differs from those of the established LIs; my assumptions are largely based around the way
I would plan out these routes and therefore could be wrong but I believe they are consistent with what we've seen up to now.
For the LIs, I believe each has 3 routes (which we'll call good, neutral and bad), for simplicity I'll focus on Jill. The good route obviously leads to her being MC's girlfriend, the neutral route would see her remain single but learn that Tybalt has not only been lying to her but engaging in stalking behaviour. The bad route would see her remain ignorant of that and become his girlfriend
Maya's route similarly has her end up as MC's girlfriend (with Josy on the thruple route or without on her hypothetical solo route*). Neutral sees her and Josy remain a couple without Patrick's knowledge, the bad route sees her being forced to leave college after he withholds her student loan and never see Josy again
With Quinn, I
believe her path is set in stone and cannot be affected by the MC's actions; we as the players can only control to what extent her actions affect
him.
To be clear, I have no knowledge of DPC's plans, I'm just basing this on what I know of storytelling structure and game design.
*
Josy would have a bad and neutral path exclusive to this route; there would be comparable neutral and bad paths for Maya on the solo Josy route