The leak initially came from an update for the Wii U version. Unless there was a change of plans (Ex: The work on porting the characters to the Wii U was scrapped in favor of doing an NX version), there's a decent chance that the Wii U will get the characters once Empoleon is officially announced.I don't care unless they decide to actually support the wii u version like the international community already has.
Unless they're waiting for all 3 it's a joke that the wii u version hasn't gotten the content update.