Best answer by Jeff S
At this time there will be audio playback issues if you are streaming from the storage on an iOS device while you have active non-Sonos AirPlay devices on your network. You can either disable AirPlay on non-Sonos devices, or disable auto lock on your iOS device.
Your best option is to offload your music library to a computer or NAS drive, then set up a music share. This will allow you to use any controller to play your music library, even if there are AirPlay devices active and your phone goes to sleep, or offline.