The anime comes out around one week after the games, but the episodes are planned and (possibly) done months in advance. Pokémon XY's first episode for instance had clips of it showcased as
early as July, four months in advance from its series' debut. Something like that happening with SM would mean its early episodes were at least worked on around midsummer, and characterization for Pokemon like Mimikyu, Rockruff, Rowlet, Litten, Bewear, and the like were probably pegged even earlier.
So even though the anime didn't debut until after summer, details like characterization would've been available at least around that time. Thus if Sakurai came to TCPi and was talking to them about Pokémon characters, they probably would be able to give him details on things such as Mimikyu's hatred of Pikachu or Rowlet being a little sleepy ball of fun.