As you know, the Pi4 has reshuffled the connectors, so I had to print a new front for this box. I will include the correct images when I make the final version, after testing full functionality.
On AliB you can find many step-down converters. The one I used is sealed and converts 8-52 down to 5V at 3A. For the Pi4 it is plenty, but I'm not sure about the USB peripherals.
For the Canon I found a battery adapter. When empty it has plenty space to add electronics to convert the 12V down to 7.2 or so.
I really should add some fuses to the 12V outlets, especially for the case I use a battery instead of net power supply.
I attach the box with velcro to the RA housing of my NEQ6, all that is left routing off-mount is one power cable!