You don't HAVE to use connectors with EXACTLY 10 pins .
If this is not a commercial project, a good idea may be to repurpose a very common connector that would be very cheap to source, like a D-Sub connector, for example get a DB-15 one and use multiple pairs for power (if it's even needed, in theory each pin in the d-sub connectors can carry up to 5a).
If you go that route, you have options, you can go with connectors like
this one that have pins, so you can solder a tiny pcb with a single connector to it (or two, one for power and one for data) or you could get one like
this one where you can simply get a ribbon cable and press-fit it and then solder the ribbon cable to your pcb or install a connector to go in your pcb.
And these d-sub connectors also have ready made holes through the metal, allowing you to easily screw them to a case.
AND you don't have to mess with crimping tools if you don't want to this way. And you'd be able to simply reuse a commercial vga cable to connect your two devices. There's plenty of vga cables around that length you want.
ps. also why carry 12v AND 5v through the cable, couldn't you simply add a LDO or a tiny switching regulator to produce 5v from 12v? The voltage drop will be small on 6ft of cable but nevertheless will still be something. But if you lose the 5v and get the number of wires down to 8 or less, you would be able to even repurpose an ethernet cable and ethernet jacks and simply use 6-10ft ethernet patch cords between your devices.