Why would they be confused? Movies find ways for people to come back from way worse things than that...
True, but it would be necessary to devote screen time to an explanation; either showing it, or having exposition of it. Can't just have him show up and say to the casual movie goer: 'Because he didn't die in the expanded universe dumb-shebs! Read-a-book....GAWD!'
I just can't see them spending the time to do this for an ancillary character; unless he is somehow going to be a major part of the story. And given his treatment in previous films; it would seem awkward if he was.
I love boba-fett; but part of his coolness is that he IS in the background. Mystery is what made him a beloved character. Too much exposition could ruin him....for the casual Star Wars fan. He's been done to death in the EU, and I don't think it's for the better.