Have we really come so far from Scream (1996) as to ignore the existence of communication-screening technology in horror movies? More realistically, the main characters would have blocked John Carver's account right away, and maybe restricted their pages to close friends if they already hadn't.
Would they? I'd think at least some of them would let curiosity/fear get the better of them and not block the account just to keep tabs on it, especially after the first, very theatrical, murder shows that the threats should be taken seriously.
Mitch having his wife killed is one tragic event that happens but finding out that his wife cheated on him is more depressing and we did not get to see his reaction, but it will leave him broken to find out.
Why did the killer murder Lionel, the performer in the parade, when he'd previously used a tranq gun? He needed everyone panicking and disorganised to kidnap his targets. Tranqing the guy wouldn't have the same impact. Moreover, a careful observer might've noticed that Lionel was at the RightMart riot, and it was his cart that scalped Amanda's head after she was killed by Lizzie. So the Carver was killing two birds with one stone.
The Carver isn't merely one step ahead of the police, Newlon is two steps ahead, as he very likely orchestrated all police operations around his traps.
That's how he knew to prepare for the police protection around Yulia, he likely assigned that officer, and made sure it was one who wouldn't be taking the job seriously.
In a small town like Plymouth, it's possible that a shop like Right Mart would be the only place in town to buy electronics, as superstores like that tend to choke out other local businesses. That means that the Carver's plan, which depends to a significant extent on consumer tech, required the use of a lot of stuff that he's likely to have bought at Right Mart.
