When Harvey opens the yearbook to the teachers to see Gerald Crane, several real people from the crew are listed.
Mr. Todd Baxley - Band. Todd Baxley is second assistant accountant on Gotham.
Mr. Charlie Reeves - Choir. Charlie Reeves is a script assistant.
Mr. Jack Bavaro - Chemistry. Jack Bavaro is a production accountant.
Mr. Daniel Gay - class not seen. Daniel Gay is a production assistant.
Possibly Lauren Rockman - Speech, but the name isn't shown in full. Lauren Rockman is an assistant art director.
Babs Olusanmokun, who plays Mace in this episode, becomes another DC/Marvel crossover actor. In 2017 he played Sowande, founding member of The Hand, in The Defenders on Netflix.
Peter Jay Fernandez, playing Dr Anderson towards the end of the episode, crosses over from DC to Marvel when he becomes police Captain Tom Ridenhour in season 2 of Luke Cage on Netflix.
Fish Mooney gives Mace a nickname: "doc". Babs Olusanmokun, who plays Mace, goes on years later to play Dr. Joseph M'Benga, the USS Enterprise's chief medical officer, in Star Trek: Strange New Worlds (2022).