mine a scratched espacialy on the tank also, all little tiny scratches in there from me carryin stuff on the tank.
Turtle Wax with Teflon (gold cap) is great for your bike, and you can rub it onto the exhaust, extra thick coat on the bit thats behind the pannels and dont rub it out there, tailpipe and silecer you put it on and carefully rub it out.
Bulb in the dash can be a pain to change, its in a rubber thats inserted in there, just pull it out and take the bulb to an autoparts store, they should have them. its not the bulb you linked to.
That gasket is fine, rub it in with some grease before fitting it.