Dark Samus makes no sense, Dark Link isn't Link either but is just an alt costume.
True Metroid is under represented but the game franchise is about exploring planets, mostly alone. You don't have that much recurring or iconic characters after Samus and Ridley.
Zelda still have only 4 and no newcomer (and only because Sheik is standalone now), it's very weak compared to the franchise power and numbers of characters. Also weak compared to Fire Emblem. Ganon should be a given (no bad character yet) and I will hope until the end for Impa.
Regarding fakes or leak, several things comes to mind:
Sakurai just said everyone can't return, and the leaks are about making everyone return or almost that;
Sakurai said number of character can't be extended for obvious balancing reasons, and Brawl was almost at the limit;
Sakurai said he don't want clones as far as possible;
So "leaks" made of Shulk and a bunch of clones returning dont exactly get my attention.