The ME system is a stand alone mini mixer of sort and connects to the D Snake expander jack on the 168 or monitor jack on the 2412.
They do not control anything within the mixer or stage boxes.
In the mixer IO set up you map the input channels to the channels on the ME system.
You can pass the cat cable jumper from one unit to the next or feed the directly from the ME hub. If you don’t use the hub each ME will need to be also plugged into power.
Both are 16 channels, the ME500 is a fixed 16 channel unit and will follow the first 16 channels you assign to it, the ME1 still has 16 channels but the user at each ME1 unit
can assign what channels they want in the 16 slots on the ME1.
That all said if you don’t want more cables on the stage they may not be what your looking for.
How many total IEM mixes do you need?
If you want to just control mixes on the mixer and their outputs the QU YOU app is perfect for that.