Tbh I still think ATs are the hardest deconfirms, and DLC costumes generally don’t bode well but Spirits are definitely Free Real Estate(TM). So I don’t think we’ll see Rex, Sans, Waluigi, Isaac, Ashley, Lyn, Skull Kid, Spring Man Yuri Kozukata why does everyone forget her ;-; as playable.
Elma, Bandana Dee, Octolings, Medusa, Mecha-Fiora (who would in fact be the second instance of Final Smash and Playable Character at the same time too), Black Shadow, Pauline (despite being a Stage Element), Ninten, Dixie Kong, Shantae, Rayman, Geno, Chorus Kids etc are all fair game though. Maybe a few third parties like Dovahkiin, Doom Slayer, new Bandai Namco character, Phoenix Wright... but not as much third parties as the pass overall.