I tried to do a livestream last night on Facebook, using OBS, which I’ve used a lot for making videos, but only a couple of times for streaming. I ran into the 2-channel limitation, which unfortunately I only discovered after the fact as I was monitoring through the room speakers rather than the computer’s.
So it ended up far more minimal and techno-shaped than expected (or heard at the time), but not too terrible for a first outing; I’ll just have to do it all again at some point, now that I’ve figured out how to route the second mixer into the first…