They way over-complicated it. Once he installs loyalists (as in their step 1), he can just round up anyone he wants, send them to a private prison run by an aligned billionaire, and ignore the courts. If the people in the departments controlled by the executive are willing to break the law, Congress and the courts don’t really have any tools to combat that.
Right, and that’s assuming he doesn’t just use his “dictator for a day” plan to remove anyone from Congress that opposes him. That’s how other authoritarians create a sham democracy.