That's intriguing to add a USB port and what looks to be an additional 12V port (in addition to the cigarette lighter serving the same purpose). Or are you considering using that port hooked to a power inverter to get 120AC out of it?
For the USB port, there's also plenty of options to buy inexpensive USB chargers that plug into the cigarette lighter. I have one for that purpose.
And instead of blocking off the coin slots, could two of them have been repurposed to be the USB & 12V ports you added to minimize the surgery & work you're doing to the console?
Just my two cents. I like the direction you're going, but these ideas popped into my head to ask.