... I do have to question, you said "teams for each region" and you've got pikachu charizard and eevee for every region, surely they just count as kanto pokémon? I mean, sure sylveon counts for kalos, espeon would count for johto etc, but c'mon kid, you have zero way of accessing pikachu charizard and eevee in unova. That was the best/worst feature of unova, completely new pokémon.
I'd also like to clarify, would this be in the generation they were released, or would this be, using gen 7 logic/physics?
Either way, I'm going to try and give this a whirl....
Kanto: Gengar, Starmie, Gyarados, Snorlax, Machamp, Venomoth
Johto: Typhlosion, Foretress, Skarmoury, Wobbuffet, Espeon, Kingdra
Hoenn: Chimecho, Absol, Manectric, Flygon, Blaziken, Sharpedo.
Sinnoh: Skuntank, Mamoswine, Togekiss, Garchomp, Spiritomb, Weavile
Unova: Janovii, Gigalith, Ferrothorn, Volcarona, Haxorus, Zoroark
Kalos: Klefki, Talonflame, Greninja, Vivillon, Noivern, Tyrantrum
Alola: Mimikyu, Mudsdale, Ribombee, Vikavolt, Golisopod, Dhelmise
Most of these work as either favourites from each generation or favourites to use each generation, but oh well