As 1900 wasn't a leap year, Frederic's 21st birthday would be in 1944, not 1940. (Leap years don't occur in century years unless they divide by 400.)
Watch the little pirate that the pirate king leans on when the pirates are singing their bit in "If he's telling a terrible story..." That little pirate is singing the same as the rest of the gang but his mouth doesn't seem to be able to keep up with the words.
Major General Stanley has 24 daughters, yet they all seem to be similar ages, which is unlikely unless he had affairs with several women.