Other mistake: When Chris sees Mrs. Doubtfire in the bathroom she is standing up and peeing, in costume. All the scenes where Daniel is putting the costume on shows that the fat suit is a body suit, in one piece, and there's no opening in the front. So he shouldn't have been able to pee without taking off the whole suit.
Other mistake: At the start of the film we see Gloria Chaney, the Hillards' neighbour, drop a rabbit at her feet and then shout 'shoo' at it whilst pushing it with a brush. If she had it in her hands, why didn't she just drop it outside of her garden, instead of at her feet, making her have to push it to get it out of her garden?