I would say Meowscarada since we did have Incineroar as a second Fire Pokémon fighter and Greninja as a second Water Pokémon fighter for SSB series. I do feel like adding another Fire Pokémon would be too much for the entire Pokémon Reps in the SSBU roster. People included myself wanted Decidueye as the next Pokémon Newcomer in SSBU before Incineroar was announced. (Plus, as well as including another Bow User into the Roster as well.) I still like to see another Grass-type be added with the entire non-Kanto Full Starter Evolutions.