I did install a primer bulb, and I can easily hear fuel doing the whole circuit right back to the tank. (I can hear it falling back into the tank.) I wondered indeed if this would be sufficient enough to clear the air out of most of the fuel system...

Beyond this, I also have run the lift pump by hand and have verified that it is working (although as I mentioned earlier I wasn't sure if what I observed was normal). I get about a teaspoon of fuel with each depression of the lift pump lever, and I can see this oozing out at various points when I loosen an air bleed screw at said points.

I probably could rotate the engine by hand... with the decompression levers open, the engine turns easily (at least for the starter). With the levers closed, there is enough compression to require a stout starter motor. I can quite easily distinguish the difference in the load. (while this does verify some compression, it doesn't verify the right amount of compression... however, when trying to start it, the engine sounds much like it did back when it ran).

If there is one area in the fuel system in which I have doubts, it is from the high pressure pump to the injectors. I can't seem to get enough fuel in those lines to make it ooze out when I use either the lift pump or the bulb...

I also wonder if perhaps I have a clogged exhaust... which may have been the problem in the first place vice a clogged filter. But to remove the elbow and all that attached to it is a relatively large task that no doubt also involves rusting bolts. But if I feel air pumped out of the exhaust when I crank the engine, shouldn't that be an indicator of a clear exhaust system?