Everything else, including Book of Shadows, which notably did not have the involvement of the original filmmakers, I would not consider canon.
Curse of the Blair Witch is canon, the Blair Witch Dossier is canon, but like The Blair Witch case files, those young adult books [aren’t].
I made the decision with my research that anything that had the involvement of the original filmmakers, which I would say I would include production designer, Ben Rock, who directed the TV documentary.