In looking at your pictures, it isn't clear what the solenoid closest to the radiator is for. I would need a better picture of that one. I believe that the toggle switches are to disable the solenoids so they cannot be activated from the drivers compartment switches. The one closest to the firewall (the switches and solenoids are mounted on the inner fender pan) might be for controlling the siren, but it would have been a very small siren based on the wire size. If I were there, I would purchase 2 new switches, and cut one wire at a time, and make a new wire, and hook it up exactly as the old wire is hooked up. Doing one wire at a time will keep you from making mistakes. I am only going to address the switch that is on the right at this time. I have no idea what the rear switch is for, and will require better pictures of the wires attached to it. There is no question that the switches are no good, however, as for the solenoids themselves, they might still be serviceable. Also take good pictures of everything before you start any work, and preserve the pictures on a place other than you phone. That way, if you loose or damage your phone, you will still have the pictures. Also, purchase like colored wire, and terminal ends. I can't tell for certain if it is 12 gauge wire or not, so you will need to take one of the wires with you to the auto store to make sure that you get the correct wire and terminals.
The large red wire on the solenoid that I mention above, I believe comes from the battery. I wouldn't mess with this wire presently, until it is confirmed that it needs work. There is a "fusible link" going from that terminal to the small terminal that feeds power to the solenoid from the large red wire. There is also a smaller red wire that goes up to the switch, and it appears that the other side of the switch goes to the green wire, that disappears in the picture. Please let me know where that green wire goes. There is a small green wire on the 3rd terminal of that solenoid, that goes through the hole between the 2 switches, and appears to go toward the cowl of the car It will be up to you to determine where that wire goes from the solenoid. Once I know where each end of the green wire goes, I can better figure out this circuitry.
Now, if I were there, I also would spray the side of the inner fender pan with Simple Green and water, and lightly scrub around everything, and then rinse with water. Being that there is no battery power, cleaning up the "field" before starting work will make it easier to identify wirea, and where they go. I don't like working on a dirty engine compartment.