You're quite right, S&S: even if both selectors are moved at the same time, the gear activates first. There is also a priority valve in the undercarriage system that ensures the (forward extending) NLG comes down before the MLG as it has the airflow to contend with.
Flyingbeagle - there aren't any hydraulically powered/assisted flying controls on an Aztec (or any other light piston-engined commercial aircraft that I know of) and the separate brake system works purely by foot pressure. A number of things could cause the radios to fail, from a popped circuit breaker to a broken aerial.