Mitsubishi finished with the car by mid-day. Turns out that there was nothing at all wrong with the crank sensor or plate, and the ticking was from contact with the timing belt cover. The leak was in fact from behind the front case, as suspected, but when the RPMs were brought up, oil started gushing from the rear of the oil pan as well. Note to self: use more RTV next time. They also repaired a couple of stripped threads and bolts, and generally cleaned things up.
So, a quick run-down of everything that was done is in order. The timing belt, v-belts, tensioner, tensioner pulley, oil filter, and gaskets were obtained locally from Max Madsen Mitsubishi, and despite the negative experiences of others with their parts desk, so far I've had very few problems (although the prices require some negotiation before they're reasonable). The tensioner tool was made by my better half from 5/16" bar stock (threaded as 8mmx1.25, then a couple of nuts at the top locked together to make it useful). I picked up the Unorthodox Ultra SS pulley set from Horsepower Freaks. When it turned out the front case was cracked, and when the alternator was damaged (doh!), I ordered both up from Conicelli, and to get the crank bolt off so I could remove the timing and balance belt sprockets, I ordered a crank wrench from Dejon Tool. I ended up back at Max Madsen after the whole thing was done, to have them clean up a bit that I wasn't able to do before the weather (and my neighbors' willingness to put up with the jack stands) went south.
So, now that it's drivable again: the alternator replacement seems to have rectified some of the low-idle headlight dimming I was getting before; while it didn't bother me, it's nice to see an improvement. The balance shaft removal was almost completely unnoticable; you'd never know it had been done unless you were really listening for it. There is a very faint high-frequency vibration, but it's more hum than movement; I can barely feel it in the cabin, but I suspect that it would be very noticable with less flexible motor mounts (mine are still stock). Because of how long it's been since I drove it, my "butt dyno" is a little off, so I can't really say if there was a noticable performance improvement. I'm hoping to get up to GLD in Wisconsin this weekend (normally, I'd head over to Rt. 66, but they're closed for the season) for a test-n-tune day, to see what I can dial in for a best time before the year is over.