Under iOS7, is the primary ANCS Service meant to be constantly advertised, or does it need to be enabled in obfuscated settings / implemented using a custom CBPeripheralMana
The ANCS is not advertised on iOS, I used a following way to achieve a long time connection with ANCS:
My peripheral device uses a dummy service, which is advertised. An iOS application is used to discover a device with this service and to create a connection. You can write your own application, or use one of free available (like LightBlue for example).
Once a connection is established, the peripheral device enumerates all services present on connected iOS device. Beside of others, there are those three mentioned in ANCS documentation.
If your register notifications for them, you will get ANCS data.
If you bond devices (iOS and peripheral), ANCS will automatically care for connection (re)establishment any time, if it found bonded device being advertised.