Frank Sully is listed in studio records as the bus driver, but he was replaced by Matt McHugh. A modern source lists Fred Warren as police surgeon, but the role of the coroner (the only surgeon in the movie) was played by E. Alyn Warren.
Although Harold Minjir is credited with the role of Tauro, the character is actually played throughout by a heavily made-up Henry Hull, whether the scene features the "real" Tauro, or Dave Duvallo (Hull's credited role) impersonating him. Minjir may well be the actor who dubbed in Tauro's definitely different voice (again, regardless of whether it is supposed to be the "real" Tauro or the disguised Duvallo on screen), but this is unconfirmed.