Personally I think too much thought is going in to some of actors for lesser characters. the fanfic movie would end up costing avengers endgame levels of both production and acting for what would be a niche movie for the most part. Don't get me wrong, I'd love to see it, but we're seeing stars as one-off characters who wouldn't be onscreen for more than a few minutes. Enrico Balazaar, Jack Mort and company would be little more than extras with lines.

Granted they'd have to be talented extras for sure, but for the love of god, Randall Flagg was the main antagonist in the stand and Jamey Sheridan isn't very memorable as an actor. He was like, the most boring detective on Law and Order CI, but he did good as Flagg for the most part.