If your headlight is OEM then it is sealed. I have replaced headlight bulbs (even LED's) in old, sealed headlights. You will need a fiber deburring wheel to remove the lens crimp to release the glass lens.
Using a strong soldering iron (no flame) you can melt the lead solder and release the bulb from the reflector base. Install new bulb and reseal lens with clear silicon gasket maker. Then solder leads on the new bulb to connect to the harness.
That oil leak? Like my 62, the push rod seal and or the shiftshaft seal weeps after a few miles of use. The aforementioned seals may not be as robust as yesteryear seals and/or shafts may be rough or worn. I gave up trying to fix the occasional oil drip. My kitchen got a new cookie pan and the 62 got the old one.