We're troubleshooting it all the way through. Your diagram helped a bit. Here's the kicker: We jumped the power to the fuel pump and it started. We jumped the main relay harness and the car started (equilavent to turning the key all the way to ignition)
so we're figuring that somehow there's no power going INTO the main relay to power anything up. I now have two main relays that work (we put it into a del sol to test and the car started right up.) so we're headed somewhere. Just where, I don't know yet.