I honestly feel like Clips was purposely fed that info by someone at the studio to distract people from real spoiler. ViewerAnon said his trusted sources from 5cream gave him the same info so when he received the real script he thought it was fake until he saw the full trailer (not the teaser we saw).
When it comes to Sidney, I do believe they would’ve blocked off time for her to film but we have no way of truly knowing if it happened. I know if it was me, I’d move heaven and earth to make it happen, even if it had to be filmed after the main film wrapped. Paramount is 100% wrong for doing that.