It's a pretty big warning sign, for me, that you feel the need to police your game by having the plot be carried around by one or several overpowered characters so people can't mess with it in-character. Not only do you, as a GM, have no need to step down to the players' level and can just tell someone who's being a disruptive dick to get out and keep your roleplay going without them, it also sounds like you're basically trying to make it so people can't step out of whatever you planned for them, sans a few details that may or may not change. While that's well and good for books and videogames, it's not so good for a roleplay where the people playing are supposed to be the main characters and where the story is supposed to be built around them and their actions, not in spite of them.