If you sing a cover song and change something about the track (whether it be lyrics, timing, key), your cover has now become a derivative work. Think of it as deriving from another piece of music and, therefore, become something new. You will ALWAYS need permission to do these.

You Can’t Have Good Music Without Percussion
Percussion instruments are very old and have quite a history. Often used in folk music, these instruments add variety and a rural charm to music.