"Encounter Okidogi, Munkidori and Fezandipiti – three Pokemon celebrated by the people of the village as heroes who protected the Land of Kitakami in the past."

Source: https://www.express.co.uk/entertainment/gaming/1809391/Nintendo-Direct-September-2023-Switch-2

This is a solid plan to get started in those wanting to start a Nuzlocke challenge with only new Pokémon from the Kitakami Pokédex.

Source: https://www.cbr.com/pokemon-sv-teal-mask-dlc-kitakami-pokedex-guide/

To keep consistency across the DLC, the other Hisuian Pokemon should also make appearances around Kitakami, not just the starters.

Source: https://gamerant.com/pokemon-scarlet-violet-teal-mask-dlc-hisuian-starters-time-story/

While Paldean Pokemon can spawn in Kitakami, Kitakami Pokemon will not appear in Paldea, even the Teal Mask content.

Source: https://gamerant.com/pokemon-scarlet-pokemon-violet-tips-for-completing-the-teal-masks-kitakami-pokedex-how-to-complete-kitakami-pokedex/

While Paldean Pokemon can spawn in Kitakami, Kitakami Pokemon will not appear in Paldea, even the Teal Mask content.

Source: https://gamerant.com/pokemon-scarlet-pokemon-violet-tips-for-completing-the-teal-masks-kitakami-pokedex-how-to-complete-kitakami-pokedex/

With the release of The Teal Mask DLC, players are challenged to fill in their Kitakami Pokedex as they explore the region.

Source: https://gamerant.com/pokemon-scarlet-violet-how-evolve-cutiefly-into-ribombee/