TL;DR
I was sitting down to calibrate the one working 502 DMM when the doorbell rang. The nice man from Fedex found the package he had misplaced and delivered it to my door. Amy was soon aware of the fact that I had all the dryer parts in hand, my to do list went from this:
1. calibrate DM502
2. have a cup of tea and do some calculus homework
3. take a nap
Became this:
1. re-assemble the dryer.
I am happy to report that there was only one mishap, which I was able to address, which is good failure probably meant taking the dryer the rest of the way apart and putting it in the dumpster (I dunno, do HAAA have parts mules?) and buying a new one before my wife found out.
It turns out that the LG dryers, and most others I guess, are put together completely with sheet metal screws and rivets. Why? Because you can do it quickly with robotics and the stuff goes together pretty well in spite of the rather less-than-precise tolerances. The bad news: this stuff is not made be taken apart and put back together again. I found this out the hard way when the special combination sheet metal screw/washer/axle on the idler arm assembly stripped the hole in soft metal bracket it screws into. Apparently it was installed just a tiny bit cockeyed, which really didn't matter as long as you don't try to remove it again.
Luckily I was able to workaround the damage with a 1/4 nut, lock washer, and locktite. The dryer is running smoothly, my wife is delighted, and my test bench awaits.