Need more information on what all your doing.
If doing the entire DBW EFI, Holley has the Terminator X for the Gen III Hemi, and harnesses for the engine / EFI.
Then consider the various harnesses like the rearward harness (tail lights, Side markers, reverse lights, fuel sender unit, interior lighting, Plus you may want to add EFI pump wiring, rear defrost, Trunk Light, electric trunk release, amplifier power, any alarm wiring?) These are the wires running along the drivers side. I use the passenger side for the low power audio wiring.
Forward Harness (head lights, turn signals, side markers, fender signals if equipped, Horn, windsheild washer pump, Plus Optional Electric cooling fan(s), head light Relays, Brake system warning switch, under hood light, other accessories like driving lights and such.)
It's pretty easy to keep the stock wiring for the wiper motor. Not sure on the A/C heater connections at the bulkhead?
With the EFI computer, it will be monitoring temp, voltage, so might just need oil pressure, or use the stock gauges too?
That pretty much leaves the dash Harness, and it could be as simple as a stock type harness (with ammeter bypass), to a complete custom dash with aftermarket gauges and switches.
If you have other electric options, you will need to plan for that wiring if using power windows, convertible top, power / heated seats, optional interior lighting, alarm system, and such.
The majority of the connectors in the stock harness are Packard 56 (unsealed).
The turn signal switch uses a different connector style (forgot the name), and the "universal" type harnesses will want you to convert those to a packard or GM style connector. I think the re-production harness from M&H has all the correct connectors if going more the stock reproduction route.
If using an aftermarket type fuse block, and depending on where the engine ECU is mounted (usually glove box area?) you might loose the use of the glovebox?