Crank, No Start

Well, did you take a magnifying glass and a good light and inspect the injector inlets? Were the micro-screens clean? I have on occasion set myself up a battery with an old injector connector, had the injectors/rail pulled up with rags under them blocking the injector ports (don't want to get a bunch of raw fuel in the engine) powered up each injector by tapping on the battery with pressure in the rail. Gotta watch it though, sometimes there aren't any locks on the injectors and they can literally shoot out of the rail, but you get the idea. The dealio is that direct battery being applied momentarily will quite often un-jam stuck injectors. Also, there is an outfit in S Florida called FuelInjectorMan who has great prices and service. You said that it no longer starts? Even with a shot of carb cleaner or starting fluid? Maybe the plugs are finally crapped out?

I had a similar problem with my dad's '96 v6, <1k original miles, and hadn't been driven in 15 years (with a quarter tank of varnished gas). It really shouldn't have clogged up the injectors (eventually the fuel will drain out of the rail when it sits a long time and the fuel filter will catch most of the gunk), especially all of them would be surprising. I'd expect you'd hear at least a few cylinders try to kick over, but with all that you've checked, and since it starts with spray the ignition's working well, I'm struggling to see what else it could be.

You mention you'd checked the fuel pressure, how did that look? You might also want to check KOEO codes just to be sure, you never know if some rodent happened to chew some wires for you over that time too. Worst case, a set of new injectors won't set you back too far.

You could try to free them up yourself with some seafoam (or similar) on the inlet, and alternate the current (+/-) a few times. Tapping on the body might help too. But if they're really stuck, a professional cleaning or just replacing the set might be the best.