This is a really cool idea. I like your idea for Sheik and the Zelda and Link concepts that Suzie posted.
Ganondorf's concept is, in my opinion, not dark or menacing enough to fit the personality of a villain. I'd still with a black color palette for him and go with a trench cloak to replace the cloak he's generally portrayed with. I think a biker or goth theme could suit his character well.