Adding USB port for new head unit

Yes you can on #1

I would leave #2 alone

I am doing the same in a #1 area.

 

#2 is easiest because you just plug in a USB charger to Cigarette lighter adapter... That's assuming you don't need USB to port to stereo and you're using bluetooth, which I believe is the standard.

 

BATIGE 2 Pack Square Single Port USB 2.0 Car Mount Flush Cable USB2.0 Panel Flush Mount Extension Cable Waterproof for Car Truck Boat Motorcycle Dashboard 3ft https://a.co/d/6EIJuU4
Something like this might work, but you would have to verify the dimensions of the opening. It is just a blocker plate. The spot was only used on very few Pkg. 5s which have the intelligent parking assist. You shouldn't have to cut the blocker plate (AKA dumy cover). Amazon has alot of options on USB ports that fit in that spot. I know what you are trying to do because I had to do the same thing, but in a Gen 2.

 

PriusCamper, I know what you're talking about and I have that set-up currently like you said for charging, but doomoo is using the USB port on the back of the new headunit that is used for Android Auto/CarPlay or a USB drive for music. Doomoo wants to extend the USB port and make it be accessible easily in a spot on the dash.