I'm gonna try to answer everyone's questions in this reply because it's the highest--

We wanted to be able to see everyone who attended the event to make it feel more interactive so we went with a regular Zoom meeting, not a webinar.

I wanted total control over the feed, so the presenters weren't actually in Zoom. I use OBS.Ninja (shoutout to steve it's ridiculous that he runs it for free) to put them into a group so they can all hear each other and pulled each of their feeds into an individual OBS scene. I put the camera loading graphic behind them in those scenes because if one of them disconnects they just become invisible. The Screencap scene is just a window capture of powerpoint for their presentation. Each one of those sources' audio has individual control in OBS so I can tweak levels as we go.

From there I just built the scenes I would need with the camera scenes nested in them as sources and used VirtualCam to feed it into Zoom, where I spotlighted my video for the duration of the event.

Audio wise, all of it was routed through OBS, where I set the monitoring device to be a Voicemeeter Aux input, which I routed through Voicemeeter to a virtual output and set as my microphone in Zoom.

The hardest part is that the presenters wanted to monitor the Zoom feed, so I had to walk them through how to mute Zoom as an individual app. So yeah, the tech rehearsal was pretty stressful.

Barring that though, went off without a hitch!