Obviously, the buzz solution is still an option if you can pair it with joy2key. And I've used it before; it does work. I have found it to be hit-or-miss at long range, though. But you can probably buy something in the $30-50 range.
If you have a larger budget, and, you want big, meat, slappy buzzers, buy something from affordablebuzzers.com. You might have to use a remapper to make the / key work. But other than that it should be fine.
For your host "console", I'd also suggest buying a 3, 6, or 12 keyboard off Amazon or ebay. Those tend to be completely programmable. Then you can just make your own labels to put on the keys. If you buy two, you can dedicate one to each of the 12 panels, and the other to all of the other game controls. And checking the instructions, there are exactly 24 keys involved, so it's probably worth your time to do those labels to help reduce brain freeze when you're live.