I finally got some free time to tinker with it some more and test some of your ideas. Here's what I found out:
1. The small hose on the front of the FPR is dry, so the FPR is not leaky.
2. When I jumpered the fuel relay connector with the three-legged jumper, the car still does not start.
3. I checked the poewr wire to the intank pump, and it receives power when the engine is cranked.
4. I placed a hose into the fuel tank through the filler tube and heard the intank pump runninig each time the engine was cranked.
5. The connector on the AMM is tight and secure.
6. The plugs were wet and had bits of carbon stuck to them (probably washed off cylinder walls by unburnt gas)but looked otherwise fine.

Questions I'm left with:
1. Could leaky injectors be the culprit? I've heard of people having to replace injector seals, which I have never done on this car.
2. Is a running prepump guaranteed to be working correctly? I hear it working, but is it possible for it to run but not do its job completely?
These are the only possibilities I could think of. I would welcome all new ideas. Thanks, Brickboarders!