Mark Greysky is a bard at heart and that definitely includes singing. Music is a bit of a coping mechanism - while he often struggles to express his emotions, he has a bit of an easier time doing it through music and song. Not always, but sometimes. When he's able to sing, his voice is pretty good! Albeit perhaps a bit quiet.
Dancing is... less his thing. He can do a few extremely simple dances but he's never really comfortable with it. Too much attention for his liking.