Re: Reboots: The Return of Sliders (?), Quantum Leap, and Other Properties
I think it'd be great to get everyone back, but you only need Quinn. JRD is almost 80 and almost certainly wouldn't survive the fall from the vortex Rembrandt is a great character, but I don't see how he fits into a "next generation" scenario except in some kind of non-science mentor situation. Wade is another great inclusion, but could easily be included in a line of dialogue (like Jane Foster in most Thor appearances).
JOC is almost the same age now that JRD was when Sliders started. I think the most organic Sliders story is a version where Quinn, following in Arturo's footsteps, is a professor. If you want the story to be a true reboot, you can have a Quinn that never fully developed Sliding (and his student, instead of Smarter Quinn, is the one who finally solves the equation). If you want it to be a continuation, you have a Quinn that slid for a while, settled on an Earth and started teaching. You can either have him having found home or not, but if he's not home, it would add motivation to his character.
If Quinn was a slider, the cameos are easy. Quinn visits Wade (whether they're married or not) and tells her about his student. She can either support it or not. He could visit Arturo for his advice on such a similar situation. He could visit Rembrandt to see what happened to him ("don't let anyone drive into the vortex"). It could be a scene with all four of them or three separate scenes).
If Quinn wasn't a slider, you could do a cameo kinda like the other group of survivors in Shaun of the Dead. Have a group of Quinn, Arturo, Rembrandt, and Wade cross paths briefly with the new group. Either way, if Quinn wasn't a slider, you'd need him to interact with a double that is shocked that he never slid in his younger years, and Quinn can learn that he's kinda the dunce of the multiverse.
But kinda like No Way Home, I'd make the references to previous continuity played off as humor or vague enough that it could apply to anything.
**************
Quinn as Arturo is probably the easiest way to do it, but I actually convinced myself that "Rembrandt as the mentor" might also work. Rembrandt jumps into the Seer vortex, gets to a close-enough Earth Prime, settles in, and has a family. His son ends up being a Quinn-like scientist and develops Sliding. Maybe the son discovers that Rembrandt never made it home and convinces Rembrandt to come along, or maybe Rembrandt comes along to protect his son.
But Rembrandt certainly has the experience to be the mentor character and could be a good source of knowledge. You'd get a Quinn appearance via Rembrandt tracking him down for advice.