Does my entire crew (e.g., sound engineers, managers, roadies) also need a C7A Visa?

No. The C7A Visa is only for the performing artist(s).

All accompanying support personnel — such as tour managers, sound engineers, lighting technicians, videographers, stage crew, or roadies — must apply for the C7B Supporting Crew Visa. This ensures that each member of the team has the correct permit for their role during the event.