The Three Blind Mice are turned into horses to pull the coach after the wedding reception, yet they are seen moments later dancing on the organ keys. But other than the seamless continuation of the song there is nothing to suggest that the party scene immediately follows the happy couple's departure (there has been time to clear the tables for dancing) so perhaps the mice have discharged their coach-pulling duties and returned to the party for a boogie. While it's true that the sequence was added almost as an afterthought, and the final shot is of the coach being pulled by the mice/horses, we see no continuity error.