It's conjecture, but I think it's reasonable conjecture given the evidence we've seen. Sure, the main 5 had RPs, but I don't consider that much different than the walkthrough distinction: you'd be hard pressed to know RPs exist without consulting the walkthrough (or delving into the code directly). If anything, you'd think Quinn must be more dependent on RPs than the others since her path can diverge much more than theirs.
To me, everything about the game suggests the choice at the crossroads will not be the final word on the matter. I say that because: the game emphasizes the player's interest in Maya or Josy separately despite not letting you pick them; Bella's marriage remains completely unexplained; Sage says to let her know if the MC's choice doesn't pan out; the Others branch specifically mentions the MC isn't ready for a relationship yet; the variation of the Others montage for those on Quinn's path
goldenrule91 and
shazba discussed; and the splashy return of Zoey.
All of that suggests the MC will at the very least need to reaffirm his decision before the end. If so, then it must be possible for the decision not to be affirmed. In that case, isn't it logical that girls who weren't LIs the first time could conceivably be LIs the second time? As we get closer to the end, the difficulty in accommodating them decreases. I'd be willing to bet Maya and Josy will eventually get solo paths. So why not Quinn or Zoey, too?