I think that Snape would have been a much more amicable man. I think he would have had a great interest in obscure magics. I think that his fascination with the Dark Arts in school merely came from the fact that they touted the Dark Arts at Hogwarts. He would not be a cruel but he would be very strict and organized. Their child or children would be well disciplined but they would also be very good natured and friendly. I think they would be a bit like Hermione. She's got lots of discipline but she's a great friend and is very loyal. I belive that Snape would be a good deal cleaner and more happy. As far as singing and dancing goes...I think he probably would.