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In the battles with them, the camera angle is freely changeable, like minor trainers and unlike major battles (including, surprisingly, O'Nare). Plus, their designs are just Delinquents with masks on- they're definitely minor characters.
No, the trainer you mentioned doesn't use anyone else.
I wonder if a clause for Qwilfish, similarly to Wishiwashi and Dondozo, could be added, because Overqwil is a major alpha battle in the story of Legends: Arceus...