While it's well-known that Hedy Lamarr was under contract to MGM, not Paramount, this detail clearly had to be fudged in order for the plot to work.
In the revised timeline, Rufus mentions that by retaining her patent, Hedy Lamarr amassed a fortune of $30 billion, and that Bill Gates has "got nothing" on her. At the height of his association with Microsoft, Gates was named the richest person in the world by Forbes magazine eighteen times between 1995 and 2017, and as of 2018, he has a net worth of $91 billion, three times that of Lamarr's fortune.
The print of CITIZEN KANE is on six reels. It was actually mounted on seven reels.
Citizen Kane was first released in May 1941 so in June there would not have been just one print. It would have been a negative that would have had to been stolen to do harm anyway.
Someone posted in Trivia that the dress Lucy wears was worn by Katherine Hepburn in The Philadelphia Story. That film was made at MGM, where Hedy Lamarr was under contract, not Paramount.
The scene with a Roman charioteer being filmed outdoors in front of a painted backdrop on a mock city street is unlikely. Such a scene would almost certainly be filmed on a more controllable indoor soundstage, using rear projection.
In 1941, the Bronson Avenue Gate, or "Bronson Gate" for short, was once the main entrance to Paramount Pictures' studios. Now it sits squarely inside a 62-acre complex . However, to revert it to how it looked back then would have been expensive and time-consuming, even with CGI, so the gate is as it looks today (with a fountain in front).