Update: I think one of the black/white cable pairs is for the thermostat. One of the neutrals/whites is not being used, and that's probably for the thermostat.
Here is a picture of my wire box that I made. I'm guessing the right is source and the two to the left are the light and the outlet that is controlled by the switch. I have two insteon switches that have a red, black, white and green/ground wire.
When I opened it up, there seemed to be a lot of extra connections/wires, so I removed two of the connections/wires. I didn't take a picture, and I don't remember how it was configured! The middle neutral wasn't used, the two blacks on the right were together, one red and one black were connected, etc. Now I just want to get to a point where I can use my switches and not have something catch on fire!