I keep waiting for you to get to the goal. What’s the goal?
Can we assume four independent sound channels?
The Peavey PV6-USB is a stereo mixer. The best you can do is mix everything down to Left and Right. You can put anything you want on those two channels, for example microphone one and two on Left completely divorced from Microphone three and four on Right. But you only get two. In the case of the analog version of that mixer, you also have an Effects Send, but that’s mono, not stereo, so that mixer is stereo and a half.
It’s actually much worse with your analog mixer. If you have a normal Windows laptop, it has no stereo analog input. It doesn’t matter what all those pundits on the internet say, Mic-In is mono and easily overloaded. So the best you can do with that is one distorted channel.
Unless, of course, you plug an actual microphone into it.
Yes, there are some computers that can switch one connection and some laptops have an actual stereo analog input. I think some Lenovos do that. Consult your instructions.
You hit the wall channel wise. Most computers “know” what stereo is and can handle two channels with relative ease. Three or more channels of independent sound requires special considerations.
The desperation method is two recorders.
I own a PV6 and can record two sound channels very well. I also have a Zoom H4 portable recorder which will cheerfully record the other two. Both accept XLR3 connections and broadcast type microphones including phantom power if needed. So if somebody had a gun and said I had to do this, that’s how I’d do it without writing big checks.
The one downside of two different recorders oddly has nothing to do with sound quality. Because of the digital encoders, you could get two shows that slowly drift out of sync with each other. Combat that with a sync mark at beginning and end of each show. A hand clap at each end will do it. “Sync Mark!” [bang]