Why Ash's Charizard and Kingler didn't physically appear in "Alola, Kanto!" for Kanto promotion

I knew that all of Ash's Pokémon from the Kanto region, including Squirtle, along with the Squirtle Squad, had physically appeared in the Sun and Moon episode, Alola, Kanto!, to promote the Kanto region, besides that the writers declined to let Ash's Charizard and Kingler physically appear in this episode, replacing them with instead his Totodile and Corphish? Now I wonder why you think?