Airplay drops off in Smart Home environment

TL;DR: Airplay drops off often even when using designated 5GHz channel between Airplay devices in a 733sqft apartment.

I'm hoping someone here may be able to help figure out my extremely obnoxious Apple TV dropping off issues. I'm a technological guy. I even worked for Apple a few years ago. But with endless trial and error and forum searches, I can't seem to make it work.

My AirPlay for music streaming is awful. Always cutting off my music playback, iPhone 6 freezes up when trying to reconnect my AppleTV in my Airplay. Sometimes it will work if I select the mirror option, but most the time it won't.

I have a "smart apartment" and thought maybe it may be interfering. I'm using Hue for all my lights, August for my lock, Nest for my thermostat, Harmony to control my receiver, projector, and Xbox, Canary for my security system. I leave my AppleTV on.

Ideally, I'd be able to be in bed, turn on my lights, use IFTTT's Do Button to turn on my receiver via Harmony, connect to Airplay, and my music starts playing. It'll work for a little before it disconnects.

Using my Time Capsule, last night I created a 5GHz and kept my 2.4GHz network so that my smart home gear can be on 2.4GHz (since Nest only works on 2.4) and connected my iMac 27", iPhone 6, iPad, and AppleTV onto the 5GHz network. Streaming video from my computer was fine last night. My video lag was finally over.

However, I'm still having the issue with my phone frequently dropping off Airplay and my music stops playing. I have been using my Apple Watch to skip songs on my phone and turn up the music. Though today I learned my watch won't work with the 5GHz network I created last night. So if my Airplay drops from my phone, I can't connect it back to Airplay from my watch.

Is there a solution here? I'm not entirely sure what else I can try. I've done full restores on all my devices, reset networks, just about everything.

Any help or direction is much appreciated. Same Airplay issues are happening to one of my other friends who also uses it heavily with with receiver.