Factual error: Raoul is the Vicomte de Chagny and he gets called that throughout the movie, even during the auction (which shows he didn't change titles when his parents or his brother died, for example). Yet Christine's tombstone calls her a countess when it should have read viscountess - or, even better, vicomtesse.
Factual error: In the scene where the fireflies light the fireworks there is one problem: The chemical that creates light wouldn't ignite the wick on a firework.
Factual error: When they show the Nelson Eddy song 'I Love You', the set/movie shown is Rose-Marie. But that number is from Rosalie not Rose-Marie. Two totally different movies - one set in West Point not with the Canadian Mounties. There are no Cole Porter songs in Rose-Marie, likewise there are no Mounties in Rosalie. Rose-Marie's music was by Harbach / Hammerstein II / Friml / Stothart. (01:09:25)
Factual error: Before 1949, when the part of the film set in Hollywood takes place, the famous sign on the mountain read "Hollywoodland", not "Hollywood". The sign had been allowed to deteriorate and during that year, the Hollywood Chamber of Commerce offered to remove the last four letters and repair the rest.
Factual error: A scene in the second half of the film pans up over the top of the Flamingo hotel/casino facing north up the Vegas strip. The Caesars Palace sign is to the left (west) and north of the Flamingo are the Sands, the Dunes, and the Frontier casinos in that order. The Dunes hotel/casino was never located between the Sands and the Frontier. It was in fact one of the southernmost located casinos on the strip at that time and would have technically been behind, southwest of, the Flamingo in this scene.
Suggested correction: When you watch "love never dies" he leaves her because the phantom won the bet, it's implied they got a "divorce" so she is still a countess.
But, in love never dies, it shows Christine dying in the year 1910, (when the whole thing was set) but on her tombstone, it shows that she died in 1913. Since Gustave is ten years old, this would make Christine in her late forties-early fifties when she had him, which is practically impossible. This is why I love LND's music, but the story is just too cheesy and inconsistent to the original for me. Since the original creator of the musical, Andrew Lloyd Webber, has chosen to call it a "stand-alone piece." and not a sequel, I would not use it as a reference for future endeavors with the trio.
Vicomtesse and Comtesse are two completely different titles. For Christine to become a Comtesse, Raoul would have had to become a Comte, but he didn't. He remained a Vicomte, therefore, Christine's tombstone should have read Vicomtesse de Chagny. It doesn't, so this mistake is valid.