Accordingly to Still Screaming documentary, during the 2 year gap between the second and the third movie, Kevin Williamson became overwhelmed (and tired) with a lot of projects.
His treatment to the movie was that “The killers were basically a fanclub of Woodsboro kids that had formed because of STAB 1 and STAB 2. They were all doing the killings and the big surprise of the movie was when Sidney walked into the house after Ghost Face had killed everyone… and they all rose up. None of them were actually dead and they’d planned the whole thing… The motive was their quest for fame, they were trying to top [Sidney’s] Woodsboro story so they could be the legacy of their hometown.”
The whole trilogy concept was sold by Kevin Williamson along with the first script – it had two treatments attached to it. In 1998, two were successfully down and the third was starting negotiations.
“I wrote this like 35 page treatment for SCREAM (3). My SCREAM (3) took place in Woodsboro. And they’re making STAB, but they’re making in Woodsboro, so the final scene still happened in Matthew Lillard’s house, in Stu’s house. And that was sort of my ending, and mine had different killers. It was a whole different thing. But, once again, it was Bob (Weinstein) really shying away from the teenage killer”, he remembered on 2020 during the podcast Shock Waves.
Williamson’s treatment concept was fought by Bob Weinstein due the moral issues that the whole cinema industry was facing after Columbine.