D'oh, well if you ever move to a smaller sprocket that chain will still be good for something.
For oiling it, good'ol clean motor oil is your cheapest option. You could spend some bucks on "chain lube" but re-oiling once a month is cheaper, eh. Plus its a good reminder that it's time to inspect everything too, motor mounts, leaks etc.
A little clutch noise is expected, you can apply a small amount of grease to the gear to reduce the 'whine' sound, just don't over do it(for obvious reasons). Also, people have had luck gluing an old mousepad to the outside of the cover.
btw, did your leak stop? As Tom said, you should turn off fuel when not riding anyway... but we humans are forgetful sometimes...