The Camera functions are powered through the gimbal connection. Otherwise they are independent, and work directly with the Controller via 5.8 WiFi.
The Gimbal functions are dependent on the gimbal connection the for both power and all control beyond basic stabilization. Manual gimbal functions come through the drones connection with the Controller via 2.4 WiFi. Basic gimbal stabilization is provided by the gimbal system itself, and only requires power from the gimbal connector.
There are no other leads required for normal operation. The supplied extra lead (Pigtail) is only a backup of the same connections provided by the normal gimbal connector (hot shoe).