Factual error: Considering everything that happens after Lester comes down the stairs at Samantha's house around 10:05 PM, it is impossible for it to only be 10:15 when she sits down to eat pizza. Their scuffle and Samantha somehow getting Lester zip-tied in a chair alone would take much longer than 10 minutes. (00:15:42 - 00:38:28)
Factual error: Twice during the movie, streetlights are visible: once when lady Russell informs Anne of Wentworth's engagements, and once while Anne is running after Wentworth. (Streetlights, lit by gas, were indeed conceived during the regency period - but they were experimental curiosities, and certainly not yet installed nationwide).
Factual error: The Lenox Hotel and The Copley Plaza Hotel are a block away from each other. Griffin did not need to take the horse and buggy and then a bus to get there. They are way too close for that.