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The only parts in the poster seem not to use the generic pokemon posture but a special art made for the poster are Kanto (Charizard, baby Charmander, Squirtle and Bulbasaur), Johto (Lugia, Dragonite&Meowth?), and Sinnoh (pic related)
So I guess Dawn and Sinnoh Brock confirmed just because they dedictated a new art for it?