Actually they aren't allowed to play music videos according to Canadian broadcasting regulations, only Much is. This is literally the reason why they don't play videos and they can't play anything longer that a designated clip length. Instead, they are owned by the CTV media group and as mentioned, are pretty much just a vehicle to broadcast MTV programming. As for becoming a host, have you looked on their site? My guess is that they go to talent agencies in Toronto, get them to send people for auditions when they need a new host, and it goes from there.