Not so much a prediction, really, more just a possibility. But, assuming she's alive and given how Part 1 has caused her popularity to skyrocket, I would say it's not impossible that Jessie might get a promotion to being part of the playable cast. It would be just the kind of change and surprise that no one would expect but which a lot of people would like. People assume that if she and the rest of the trio are alive and return, they'll just be secondary crew like before. But making Jessie part of the main cast would be just the way to subvert that expectation and bring her back in a way no one would see coming. She could have a second gun to go with the one she already has, with both of them modded to hold materia. Between them, her grenades, and her martial arts skills, she'd have the combat ability to stand alongside the others. She could potentially become a complete bada** like Cassie Cage from MK11 (who shares Jessie's VA, btw - Erica Lindbeck), but of course with her flirtiness still intact.
Also, by the end of FFVII's traditional story route, there are only two women left in the group. Tifa has only one female friend left, Yuffie, but the age difference and her brash personality might not make it easy for her and Tifa to ever be very close. Letting Jessie join the group ultimately adds another girl to the endgame cast, someone Tifa can relate to more easily because she's already been friends with her for a long time, and allows us to still be able to have a choice for Cloud's love interest after Aerith's gone so that it doesn't feel like the only reason Tifa may have ended up with him was because she just happened to be the last woman standing.
I admit it's a long shot, but I don't think it's as huge a stretch as some people might think. Part 1 already gave her a solid foundation for this kind of thing. She has the reasons (her parents and atonement/redemption for what she feels she did with her bombs) and the connections (her history at the Gold Saucer and her contacts in Avalanche command) to make a journey outside of Midgar. And now the popularity within the fanbase for SE to be able to make it a reality. Also, consider this exchange between Jessie and Cloud:
Jessie: Relegated to stagehand once again. I'm starting to think I'll never get a starring role...
Cloud: There's always next time.
Now, it's possible that Cloud encouraging her was all there was, but what if it wasn't? What if it was also a subtle hint to her future role in the series? SE has already used foreshadowing with Jessie on at least two separate occasions - when her legs are pinned by rubble in Reactor 1, it foreshadows her fate in the pillar when she's half-buried by debris. And when she flirts with Cloud in Reactor 1 about him being the first to know if she couldn't walk, it foreshadowed that very thing in Chapter 4 when she really couldn't walk and he carried her into the bar. So it's possible this exchange could be another bit of foreshadowing as well.
Considering that it's the first thing she says when you talk to her and that if you talk to her at all before leaving for Reactor 5, you can't miss it, makes me think it might be. Also that it's Cloud, the main character of the series, giving her that encouragement, as if he were a stand-in for SE. I could be wrong, but then again, I might not be. This isn't to say that I mean she'll be center stage all the time and basically take Cloud's place in the series. I know that's not going to happen. What I mean is that this bit of possible foreshadowing might just be saying that she'll have a larger role in Part 2 and beyond, whatever that might be.