Complete overhaul aftermarket electrical system.

I doubt anybody makes a pre-wired kit that fits your customization, so you will have to do a lot of detailed planning with any store-bought kit, so you have to wonder how much easier than doing it from scratch would be. You could pay for custom engineering, but at maybe 20 hr x $100/hr, you'd probably decline.

In my 64 & 65 A's, I built my own engine wiring using a relay/fuse box from a 95-99 Jeep. If you do similar, don't go 2000+ since most of those boxes changed to connectored wire feeds to the box, which would be harder to customize. My setups allow for 9 relays, as I recall, for headlamps, ignition, horn, starter, fuel pump, fan, ... 67Dart273 did similar. Not technically hard, just a lot of work on winter nights while watching TV. Definitely a "dining table" job, not on the car wiring until the finale.