This bit is important, I think.
Any set up along these lines, it’s a must that it maintains full bass management and room correction.
If someone sets a crossover for the sub at say 80Hz, it’s vital that’s all that’s sent to the sub (whether it be a Mini, or some other device), and that any PEQ adjustments made are kept.
And it’s vital that the Pro, Pro Plus, or Ultra then only outputs above 80Hz, whether that’s over analogue or digital outputs.
If that doesn’t happen, there’s really not a lot of point having any sort of sub out facility.
By the way, this needs to be true for the Ultra, too. If you tell the Ultra you have a sub, and to crossover at 80Hz, then the high passed signal for the mains must have the same bass management applied over both analogue outs and digital outs.