After a fire.....

The engine bay harness seems salvageable... You'd have to redo the ends of the wires before they go into the bulkhead connector and then test them all for continuity and replace any other parts that look burnt up, but it would save you some dough. No matter what you do, I'd ditch the terminal connector at the firewall and find another way to join the interior harness and the engine bay harness when you redo it since you already have to take it all out. That's the weakpoint of the electrical system, and if I had to guess might've been what started the fire? I'm not sure what the premade alternatives are out there, but I can think of a couple ways to DIY it and make it safer and more reliable than the old connectors.