Yea maybe but that would be possible when Harry was alive. Voldemort probably would want to kill harry but I think he would keep him alive under some sort of curse, to prevent him from escaping...after that the order of the phoenix would have never happened...Diggory gets killed...and then probably Voldemort (Polyjuiced as Harry) would kill Dumbledore and say that it was a mistake and he was really sorry, So now after Dumbledore's death, The most powerful man is now walking in Hogwarts by the name of Harry James Potter, the boy who lived will soon be dead