This is well after the OP, so it probably won’t help him, but perhaps others will have the same question in the future.
Stephan is correct that the ME system cannot control any of the AUX outputs from any of the consoles. The ME system is specifically designed to be separate from the AUX mixes. This is one of the major reasons to use the ME systems in the first place.
However, if you want to use some physical XLR outs and an aux mix and need some sort of local box to act as a headphone amp, there are plenty of small headphone amps available. Our church uses the Behringer Powerplay P1 headphone amps for our band musicians who are static and not moving around. They then use one of the Allen & Heath mobile apps to control the AUX send levels (SQ4Y for SQ series, QUYou for QU series, or OneMix or Custom Control for Avantis/dLive).
This creates a very usable and inexpensive system for musicians to control their own mixes. Of course you have to have enough AUX mixes and physical XLR outputs on the board to handle it.
