The Allen and Heath control apps do not pass audio. You can only control settings with these apps. (I am not aware of a single manufacture that passes audio through their apps however, it’s not just an A&H omission). The reason is two fold. 1) Latency would be too high to be useful in a live environment 2) The amount of data passed would increase exponentially potentially slowing the control app way down.
The easiest way to get audio “remotely” while away from the console is to use a wireless IEM pack just like musicians use. You can hook the transmitter up to the headphone/monitor output and then in your headphones you will hear whatever you solo (individual inputs) or the whole mix when you aren’t soloing. It works really well, but it isn’t cheap. A decent system (like the Sennheiser G4 IEM) is going to start at around $1000 for a two channel setup and increase as quality and features get better.