Below minimums - Heck yes! you get to land!! ... There's honestly not a good answer for this question. The "best" answer would be to announce to ATC that you're on the missed approach. Everyone asks this question ... but I don't think I've ever heard of it actually happening before. They just want to know you're not going to try to pry the controls out of his hands in such a critical phase of flight.

Smelling like alcohol - Why didn't they ask you to join in?! ... Tell them you can smell it on them and that you'll both call in sick with food poisoning. This was he doesn't think you're throwing him under the bus. If he refuses then you'll have to call out sick to make sure the flight doesn't depart, and possibly call the DO (duty officer).

Nav light - If one is out you still have another. If they're both out well then is it day time? If so, you're legal. If it's night then that just sucks. Try powering down the aircraft and then back up .. it's actually worked for me before. If nothing works ... It's happened to me before except I didn't say "I fixed it, let's go" ... had to write it up. Granted it wasn't the night before a holiday or anything like that ... but still.

Hope this helps... PM me if you have any other questions.