In your second photo, this is where your 3 pin harness connects to. It plugs into a short harness that goes to the fuel tank lid.
The other photos after the 3 pin, I have no idea where it goes. I looked around in the trunk of my car for that other connector but, I didn’t stumble on anything like yours. My recommendation is to leave the trunk unassembled and get the engine running and see what doesn’t work.