I was about to ask if you changed the filter...The sudden stalling and inability to start could have been a filter issue at that point. If the filter was bad enough from sucking debris off the tank bottom, it may have disintegrated and clogged the pressure regulator. Recall, you did have one point where the removal of the regulator and reinstalling it seemed to help...I commented that the pressure regulator may have had a clogged passage that cleared.
Debris like you describe, from either the sludged tank or a filter coming apart, could create fuel flow issues or clog the TBI fuel inlet, pressure regulator or ports/passageways within the TBI unit. As professionals, we don't like to borrow trouble, right? So, my approach is always systematic and aimed at eliminating immediate symptoms. Here's what I would do now:
1) Confirm fuel pressure from the pump, making sure it is within the 27 PSI or so maximum.
2) If the pump pressure is correct, I would verify fuel pressure past the regulator. It must be limited by the regulator to 14-15 PSI.
3) Once you have uniform fuel flow at the regulator in terms of volume and pressure, turn to the passages in the TBI unit, between the pressure regulator and flow nozzles.
4) An often overlooked sensor that can create a lot of trouble is the crankshaft position sensor at the back of the engine on the upper bellhousing. Oil and debris can cause this sensor to malfunction or work intermittently. Many overlook this as a trouble spot and chase after other issues. It takes only minutes to access this sensor, remove it, and clean it thoroughly with spray carburetor cleaner and a rag. If in doubt, do an ohms resistance test on the device.
Make sure you do not have too much fuel pressure past the regulator. If pressure is high, determine whether this is a pressure regulator malfunction or a fuel pump with excess output pressure. You had many times that the engine ran well then suddenly went into some form of fuel flow failure: too little, too much, etc.
Note: At this point, with all of the flooding, the oxygen sensor and catalytic converter may be overloaded. You may need to clean that up to restore a normal idle and closed loop functions.
Overall, though it costs for diagnostic equipment, you likely could benefit from a search for DTCs. A DRBII or aftermarket scan tool (Snap-On or OTC Genesys) with hook-ups for the Jeep TBI era could prove helpful. Any code reader that would hook to your diagnostic plug could at least retrieve stored codes from the ECU. Look for an inexpensive code reader for your pre-OBDII era Jeep.
I'd be surprised if you have no stored codes at this point. I would clear the codes and get a fresh read, as there could be several sets of stored codes with some problems already remedied.
At this point, I'm thinking a dirty crankshaft position sensor, high fuel pressure or a fuel pressure regulator malfunction. Functions of the ECU typically work or they don't; seldom do they work intermittently, which makes me think in terms of a "mechanical" device rather than electronic. (I would, however, check wire connectors for corrosion and contact integrity.)
As you share, you've exhausted a variety of sensor possibilities, not to mention your wallet, chasing this around. Onboard diagnostics and fuel pressure tests can demystify and at least confirm or eliminate trouble spots. Stop the flow of money over the parts counter until you're absolutely certain you have a malfunctioning part...
Unless you've exhausted your tools or patience, there's much to be gained by following through. Be systematic like your heavy equipment repairs and troubleshooting. When you do find the culprit and fix it, you'll have far more trust in the Jeep.