I do believe that Fett survived. Unlike Mace, it can be proven that he survived. The EU graciously supports this. Since the movies never say specifically, and the EU does, that means he's alive. I've always thought of the possibility of Bail Organa surviving the destruction of Aldaraan. In that I mean he could have been away from his planet when it was destroyed. Though Leia never mentions or sees him again, so it's not likely. Most take it as common sense that he died. But, you never know. The whole debate on the emperor, you never know on that either. He might have climbed out of the pit after grabbing on to some object on the walls of the shaft. I strongly believe though, that Mace died. If it weren't for the book saying he died, I would agree with SilverWook.