I mean, realistically, who’s the least likely to come back?
Anyone first-or-second party is probably safe because there’s literally no reason why they can’t come back.
Going off of third-parties alone...
*Snake: Gone. Metal Gear is dead. Fuck Konami.
*Sonic: Pretty safe. The long-time rivalry with Mario and all that.
*Megaman: Depends on what Capcom intends to do with the IP. Hasn’t been seen since MM11.
*Pac-Man: Even if Bamco doesn’t help out with development anymore, he could still stay in via recognizability.
*Ryu/Ken: More than likely to stay, possibly joined by a new character from Super Ultra Street Fighter V Alpha HD EX Turbo Remix Championship Edition & Knuckles Featuring Dante from the Devil May Cry series.
*Cloud: Could go either way. Either replaced by an FF rep with greater ties to Nintendo, or kept in to advertise future episodes of FF7R.
*Bayonetta: So long as Bayo 3 remains Switch-exclusive, there’s no real reason to cut her.
*Simon/Richter: Even if Castlevania as a game series may be dead, they could always replace them with Trevor as a tie-in to the Netflix series.
*Joker: Probably the most recognizable Atlus character. Only question is whether Sega deserves a third rep.
*Hero: Will always be huge in Japan. Worst case scenario, he might get a new alt to tie-in with Dragon Quest XII.
*Banjo: Gone. Dead franchise owned by a direct competitor who only got in due to a literal miracle.
*Terry: No idea. Don’t know how relevant SNK or Fatal Fury is right now.
But even if all third-parties were to be cut, that would only reduce the roster size by twelve + two Echoes.