Bringing the Thunder
Besides we don't even have a Eeveelution of each type yet it seems a bit early to be getting into duel-types just yet
In reguards to the Holiday thing I think it would be great if Seasons come into this Gen then I don't see why not maybe we can get special outfits for the Holidays and like said maybe on certain Holidays certain pokemon become more easy to catch like on Easter would be Rabbits and Birds on Halloween Ghosts and Dark Types and on Christmas Ice and certain other Pokemon
They could also add in Japanese festivals like Obon (Almost like Halloween) and that one I can't remember the name of off hand it would make Celestual Pokemon easier to catch and im sure theres French Festivals/Holidays so you could add those too and make up some Kalos exclusive Festivals/Holidays
Holidays are too much of a cultural concept, I can't see them doing that.