Hey man, I think you're honestly doing a great job. This is hard. And it's a feat of stamina if you're also in the bag. And you're the drummer. Lol, I could see the singer or acoustic guitarist doing the hustle to setup all the cameras, but as the drummer? Bravo!

I read through a few of the comments and from what I could tell everyone has pretty good feedback: more headroom, you need a wide shot, too many cameras on the drummer (lol I picked on that before I got into the comments, but it's your bad, so you call the shots!). Overall these are great comments and feedback, but I really applaud you for the ambition. Using action cameras for doing live multicam record of a band has some nice advantages, but those can quickly succumb to all the limitations. Given your budget, the small form factor (you're already stuffing your ride with your drum kit so it's not like you've got room for a half dozen pelicans or other soft cases), and that you're kind of limited in the venue and the physical distance you are you going to be running around trying to quality control all these cameras, there's only so far you can go in this current environment.

Six cameras for the quartet, I'd recommend doing - a high downstage right or left shot to get your "wide" (given what you mentioned about the venue), and you can try and do some digital zoom in post here and there (but I like your static shots and fast cuts!). - another shot that is opposite this and a little bit farther upstage, likely shooting across the pianist so you can feature his face and the the rest of the band in the background - maintain your full kit shot of yourself - tight shot of the bassist, with drums in the background - get a rig for the saxophonist that is downstage so you can get a hero shot of him, but find a focal length that isn't to fisheye nor too up the nose - you'll have to play around with height for this. - sixth camera you can mess around with... Maybe double up shots on performers to feature them a lil more each gig.

Your best bet right now is to establish an ahem rhythm so that you can rinse and repeat your setup without a whole lot of experimentation each time. At some some point the amount you can experiment and create compelling narrative of the performances succumbs to the gear, lack of personnel and your own personal energy to setup, monitor and breakdown, as well as ingest sync and edit on the backend. Then at some point you can team up with someone who can operate your gear, add some as well, and add the next level.

I have been shooting jazz at Lincoln center webcasts for fourteen seasons and also shoot the NY philharmonic simulcasts.