So far, Music101 only allows one channel to be sent. I've used Loopback to gather everything into one channel. That being said, I could also utilise a nifty program called Ladio Cast which pushes multiple inputs through to one sound driver.
Today, I tested Music101 with a friend in East Melbourne.
I began by using the GCP server (based in Sydney) and the sound was choppy. I immediately moved to a server set up from my home and the sound was much better. This makes sense, because the audio is being sent to me, rather than out and back again. That being said, for the person on the other side of the call, the audio would break up intermittently. They were on wireless, and it's strongly advised that users use Ethernet.
Out of curiosity, I wanted to see what happened if I connected with someone over wireless. Seeing as hoping that people have ethernet capabilities seems implausible at this point. We managed to play through multiple tunes with no delay. Honestly, I was very surprised! It's been the best trial so far, of any software we've played with.