Hmm! a lot to take in there. Unused wires you may have found:
Regarding switch you have top left. It has the icon for front fog but it's not clear on your pics if you have similar rear fog switch which I would expect to be top right. This should have similar icon but with beam lines sloping downwards. Can you confirm?
In my car the icon for front fog has the three lines to the left of the lamp and sloping downwards. It lights up green.
The rear fog icon has the lines to the right of the lamp as in Montegue's photo above. They are horizontal and light up yellow. My guess is that the switch in the photo is for rear fog.
Easily checked if the fog lights are hooked up as suggested.
