I didn't get around to pulling the head off, but I was able to push the #1 piston up and down with my hand. I pulled the lower bearing off the crankshaft on the #1, and the crank pulley was then able to turn. The crank bearing was in pretty tough shape when I got it out, but I'm not sure what actually caused that bearing to fail.
I know the PO was into this thing before I bought it, and he did very poor work. There were missing nuts and bolts in both critical and not so critical places, and some standard nuts/bolts jammed on metric threads. One example was a standard nut on one of the transfer case studs for the driveshaft. He was a real hack, so I wonder if he wasn't into the oil pan before and messed something up. I have a feeling his poor attention to detail is the true cause of this failure.
All said and done, I hope this is the only 3FE failure I have to deal with for awhile!
PO could have dropped the crank on the ground...