Honestly I don't expect a single other pokemon rep, ESPECIALLY from gen 7, to be playable in the game. And not just because gen 7 came out quite a bit ago and also after the ballot tbh it's just that pokemon rep is already hitting critical mass with pichu, ivysaur, and squirtle being added back. Pokemon really, genuinely has enough and the game seems to be focusing on video games as a whole.
(Also literally every argument saying Decidueye is going to be in makes no sense, none. For a grass starter that's why the pokemon trainer exists. The archetype of flying winged archer is already in the game, twice as Pit and Dark Pit.)
this plus Richter and Isabelle are the only characters that probably weren't the most popular on the ballot, and yet they're both heavily reusing assets of other characters. Isabelle is Dr. Mario levels of close. We just have 0 indication that anyone that isn't
the most popular is going to be uniquely playable.
I expect a rhythm heaven rep partly because Mr. Game and Watch has those slick new animations (practice with shifting 2d animations in Smash) and everyone thought the chorus kids were originally meant for Smash meant they voted for them a decent bit in the ballot I believe
The only other Square Enix character, who's massively popular, that I can think of is Sora.
I see them announcing him during the end of a direct after they confirm the Kingdom Hearts series will be on the switch.
Actually, fun fact, supposedly Sora is actually owned by Disney! Not Square Enix.