Thanks for the advise guys, the wireless mic and antennas are not going to be a problem; I'm using the Sennheiser Evolution G3 wireless system with two remote antennas that can be used over RG-6 since they have their own grounding plate.

The main issue is finding a reliable karaoke system that can be controlled from the stage with an iPad app. I have an outdoor Ubiquity access point 10 ft. away, wifi is going to be fine.