Honestly, Gale dying in 7 in the opening kill would probably be the most logical way to get Sidney to interact with Ghostface again. I wouldn’t string it along like they did with Dewey. Open with it and then have Sid and Kirby lead the charge.
You could probably not even make a new teen cast this time as the killer should be personal to both Sid and Kirby. And I’d bring back McDreamy from 3.
Part of me thinks they got us in 6 is because she might have died in the script and changed it when Neve didn’t return. Couldn’t lose all the OGs at once.