Never give up on the "quick fix" until you have tried a few things.
I am not familiar with your particular engine/transmission but I can offer some sugestions and you can add your observations and see what happens.
Figure out which end you can hang the ped from to move the oil away from the inside of where it is leaking, Drain the gas and hang the ped by the front or back wheel in the garage or from a tree limb.
Use a can of carb cleaner and clean off the offending joint until it is spotless, try to not get too much carb cleaner in the transmission.
Use a magnifier and try to see why the joint is leaking. If it has a gasket, has a piece of it blown out. Are the bolts, which hold the two halves together, tight.
If it is a missing piece of gasket, cut a piece of similar gasket material (or brown paper of the correct thicknes) to fill the missing space. Give the spot another spray of carb cleaner to make sure it is clean and blow it dry with a compressor or your bycicle pump. Smear some anaerobic gasket compound (see Locktite.com) on the filler piece and stuff it in the gap. Avoid pushing it in too far, you do not want the inside to prodrude into the transmission. Let it set for several hours, then trim off the filler flush with the outside of the crankcase.
If it is a crack in the casting, do all of the above cleaning and wire brush the surface, then clean and dry again. Get some epoxy putty from an auto parts store, gas tank/radiator reapair, mix it well and press it firmly in the crack, feathering it out to a thin edge. Follow the instructions on drying time.
After either fix, drain and refill the trans as there may be carb cleaner in there.
Check the application temperature for whatever compound you use, you may have to heat things up with a hair drier or do this in your living room to be successfull.
On your electrical problems, it sounds like your turn signal tell tale is connected to one of the signal lights instead of the flasher or switch common.
Your high beam indicator is connected between the high beam terminal on the headlamp and ground, this is such a simple circuit it is hard to sugest how to fix it.
Try connecting the bulb from the high beam terminal to ground, if it does not light, replace it. If it does, bypass the connections to the bulb with a jumper wire until it lights. Whatever you just bypassed is bad.