Malladus is also capable of creating dark link so he's not exclusively Ganondorf's creation, even though Ganondorf was the first to try the idea. The reason there will be no dark link is that Ghirahim's fighting style has been likened to dark link's by Aounuma I believe. Why would they have two...
I do not think the person who created these rumours actually knows if they are true or not. I think there is a high possibility of Volvagia. Alot of people believe he will be in the game so this person could have written that and hoped that people would see it as believable. Dark link is simply...