How to record a Christmas light show, with FM-broadcasted music, on an iPad?

We own an animated Christmas light show (~20k lights, 80 channels) choreographed to 4 Christmas songs; we broadcast the show music through an FM transmitter. We have iPads, iPhones; we also have digital video cameras.

We would like to video our shows, incorporating the live FM broadcasted music.

Any ideas, suggestions, tips, techniques, do's, don'ts, lessons learned???

Any/all inputs will be appreciated!