Hi psychopike. Glad to see I'm not the only one still lurking around here.
1. I think "resealing" the headlamp will work but make sure that you dry it out properly before you seal and re-install. Check for cracks in the housing though. Did you ever get the headlamp recall done on your FX? Did mine a few months ago so headlamps are shiny new now.
2. I think it is BS but don't go with the very cheapest that you find online. You usually get what you pay for. How much is the oem ballast?
3. I know others have used various companies for foglight conversion kits but I have a little experience with HID Nation when I replaced all of my bulbs with LED's. They seem like a good company and have been around a while. I'm sure they have kits for the FX.
05 FX35, Silverstone, Graphite, Touring, Escutcheon, Sport Pedals, LED Dtrl's(thanks rookie), Stillen STB, +2 Timing, Stillen CAI, LMS Z-Tube, Grrrowwl!!, Plenum is next (OK - well - actually the G35 E-brake pedal is next, but I swear, something is going to happen with that plenum).