I re-read your original question, and I guess there was some misundersting on how the Mixes work. Please correct me if I’m wrong.
You state that the Mixes “are Analog out 1&2, 3&4, 5&6, 7&8 respectively”. This is not correct, since the four Mixes are not hardwired to the Analog Outs, and can contain all the input signals from all analog and digital inputs. The four Mixes are like the Busses of a traditional console.
For example, if you have Mix 1 selected in the Main pane, you can adjust the volume/pan of your ADAT inputs, together with the volume of the analog inputs.
These inputs will be mixed in a flow that is called “Mix 1 L/R”. If you go in the Settings pane, you’ll be able to assign this flow to any of the Line Output pairs or the ADAT Out pairs.