Time to break your problem in to pieces, I think. Try this, if you can get the engine to start again - let it sit and idle. For a long time. There won't be any fuel sloshing around in the tank, just the pump pushing it around in a circle. Watch the pressure, listen to the pump and the various relays involved in supplying power. If it idles for many minutes (longer than three laps around the block at least), then you can focus on stuff in the tank. If it does the same thing as before, at least you'll have a clue, that's it not some large thing sloshing around in the tank
Then, if you want to take the tank out of the picture, run your supply and return lines in to a gas can under or beside the car. Do the same thing, let the engine idle. See what happens.
You can do the same thing as above, but without the engine running at all . Just jump the fuel pump relay or hot wire the fuel pump. Let it spin and push fuel. See what happens. Actually, that's what I'd do first, because it's quieter and you'll be able to hear the pump.
You're trying to think about too many things at once. Turn the big problem in to several small ones.