Continuity mistake: When Toad General calls for the council's attention and announces that Bowser found the Super Star, note his shirt buttons. Then, when he says that the Kongs will never agree because their mad king doesn't make alliances, Toad General's shirt is backwards, his buttons are on the opposite side. (00:24:55 - 00:25:35)
Deliberate mistake: Bowser has several teeth that appear and disappear throughout the movie. The best example of this is when Mario is trying to grab the Power Star. We see Bowser snarl at Mario before he picks him up. There is a gap between his two front teeth. However, when the scene cuts from Mario's horrified face to Bowser's face, there are now extra teeth inside that gap.
Answer: "Princess Toadstool" was used in the original English-language manual, but she was Peach in the original Japanese, and that name continued in later versions, being combined with Toadstool. Bowser was originally called "Kuppa", but presumably the English-language version resonated more with people, plus removed any confusion of "Kuppa, King of the Koopas", so the English version stuck.