I know this but has been issued before, but the former solution is not working. None of my costumed heros are on any teams, not in tourneys, war, or anything. But I can take their costumes off. Look at Mel, not assigned to any team.
Then I take off his costume on the card…
Hit X to exit and it defaults back to him still wearing his costume.
Doing this for all 3 costumed heros.