>>24913306They are all 'different' yo-kai in the sense that their stats are different from the main line or may have different soultimates/elements/inspirits. A few are just outright upgrades, though they are usually labeled as Rare in that case.
For instance, the motemote~ duo here. Cupistol involves into the pink one, carrying a wind attack and a healing soultimate, along with an +aggro inspirit. The blue one carries a fire element and has an attacking soultimate, along with a -aggro inspirit. It depends.