I'm not sure if there is a bit of misunderstanding.... Yours or mine. Apologies if I have misunderstood you.

#4 the ID40 would be a second independent zone, integrated into your 861.
#5 it is independent of other zones and would have no effect n quality of those zones.

This is where I think there is some confusion...

#1 is an incorrect assumption with Sooloos. It's not audio distribution in the old way.

If you went with an ID40 in your 861, that would be one zone for whatever area your 861 currently serves.

Your MC200 would be the second zone, if I understand, feeding your non-DSP speakers. This is totally independent of your 861/ID40 and thus would require additional power amplification if used with non active speakers.

Other than ID40 needing the MC200 for music store and core Sooloos functionality, the two zones are completely separate entities and thus what is playing on one or the other, or playing through your 861 has no impact whatsoever on what is playing on any other zone, quality or source material wise. Ie you can't play a TV plugged in to your 861 in another zone without reverting to the old way of doing things, ie piping audio signals between zones.

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).