Questions on using some original cabinet components with new setup

Hi all,

I've recently gotten an old, beaten Konami cabinet that was gutted and replaced with a Raspberry Pi setup. Some of the modifications that were done to it are a bit inartful, like the speakers wires were just cut for instance. Here's what I would like to do if it's feasible:

• solder some new wire onto the nubs of speaker wire left to extend them down into the cabinet, and use them as the audio for the machine instead of the built-in audio from the HDMI monitor currently in the cab. If I'm thinking correctly, can I just use a small powered amp to push the audio? The speakers are 8 ohms according to the service manual; can I use something like this? https://amzn.to/2DiFkNn
  
  
• There's a small connector coming from the back of the coin slot panel. It's black/red and looks a bit like a Molex connector, but with only 2 pins. I'm assuming this is just to supply power, so I can use some kind of adapter to power via USB? I'd love to get the lights working behind these without having to do some kind of LED conversion or something (unless that would be easier)
  
  
• This is less important, but there's a small toggle switch on the top of the cab. I have no idea what this was originally used for, but I would love to replace the old CFL bulb behind the marquee with a new LED bulb and use the switch to power it. Would be easier to cut replace with a new switch of some kind that's meant for this sort of thing?