I mean, everything is a possibility given how little we know, but I don't see nintendo (or any significant writer) going down that path with any incarnation of Link. It would be like 343 Industries going out and turning Master Chief into the Antagonist after being a green icon of Heroism since...
Agreed, the outfit, arm markings and hand seem a bit off for that. I guess we'll see in the actual Manga.
I don't think so. His eyes, hair and nose seem different to the usual art style for Link, on top of him only ever being depicted as a straightforward protagonist with no darkness to speak...