When it comes to copy right its a difficult to really understand cause people say parodies are fair game but it the person who made the parody does not agree for whatever reason then its game over for that video. The only thing I can tell you is use freedoms music and if it gets flagged then you have the right from freedom and said music site. In most cases I would stay away from music unless you can get some low key people who make music and let you use it for publicity for them.