The nice lady from UPS brought more parts-

Some relays and relay sockets, fuse holders, and open barrel terminals to connect it together. The parts are arriving, but I’m short a little green wire, some WeatherPack 3 connector housings, and a dual power post terminal connector.

I was a little concerned that the terminal crimper might not work, but after installing a fuse holder on the Nissan for the tail light converter power wire, I’m no longer worried. It works perfectly.