Factual error: A toy modern four-door automobile and a clear plastic ball can be seen as the children play when the Burgermeister comes in on his wheelchair. Both unlikely for a story set (presumably) in the 1800's, at the latest.
Factual error: During Kris' "A Kiss a Toy" musical number, one of the kids has a Tommy Gun. Since the story is, at the latest, set during the 19th century and the Burgermeister's troops are armed only with spears, swords, and knives, a Tommy Gun should not be in this story.