adamgw

I usually see hardware sold by individual pieces or by box. That's certainly the case on Mcmaster, where I order most of my hardware. Nuts will work too, this is just another option.

Yes you can, but some emulators might run slower like N64 or PS2. Retropie does recommend the Pi 3 for best results. But if you have a Zero, give it a try!https://retropie.org.uk/docs/First-Installation/

Once the insert heats up, the plastic melts around the insert and when it solidifies it should hold the insert in place. If the hole is smaller than the insert, there will be extra plastic to remove at the end of the insert.