Unlikely characters to wear the cape and cowl
For a time in the later golden age, it was pretty popular that there was a story where a hero has to disguise their identity by appearing in both one place as the secret identity and one place as the hero. This meant for instance that Superman and Alfred wore the Batman suit at different times to throw off the suspicions around Bruce Wayne. So those I would say are likely characters to have worn the costume. On occasion other character have worn the costume, usually as a trap to capture others who were trying to catch Batman. I am no great Batman fan, but I do know that this has happened more than once.