After a fire.....

I’m thinking of getting small fire extinguisher and cary it in the car all the time.

It's the first thing I buy for all my vehicles. The AACA requires a fire extinguisher for most judged cars. A small or medium one is not expensive at most stores. Every car guy should have one in each of their cars at least.

Then you have new wiring throughout, no compromised connectors, wire insulation that is new and pliable, new bulkhead connectors that can be packed with di-electric grease while new. IMHO this is a good investment and a cheap insurance policy compared to patching stuff together until the next piece of 55 year old wiring burns the car up for good. The original wiring lasted 55 years, if this new wiring lasts half that long it was worth doing.

Yes, absolutely. As a guy who has done control and high voltage wiring professionally, as well as parted out plenty of Mopars back in the 80-90's, I'll say this: I have cut apart and modified a few 40-50 yr old harnesses. When you unwrap a wire 8" back and strip the insulation and the copper is not bright, but already brown from slight oxidation, you are fighting an uphill battle. Wait for a YO 20% off sale and buy the M&H harness. If you're handy w electrical, and well versed in wire size and current carrying capacity, loads, current draw for DC, measuring resistance, etc, buy wire and build your own.