This is what we did a week ago:

Our custom-built rig has 8 SDI inputs (two DeckLink cards).

Used 6 cameras:
- 2x BMPCC 6K through SDI
- 1x BMPCC 6K connected Wirelessley with Teradek Bolt 4K
- 3 Panasonic PTZ camera with an operator also coming in through SDI
- Drone has been pre-shot about an hour prior to the event, even though we could go live as well with clean HDMI output and then we would convert it to SDI.

We used Datavideo for intercom and tally system, wireless camera had tally though browser on an iPhone and DIY wireless intercom.

Sound has been done by the client, so can't tell anything else but that we used Focusrite 2i2 to get stereo input in.