1993 Bronco 4WD no oil pressure

[ASJT3]

Folks,

I bought my first Ford recently, a 1993 Bronco 4WD with 192,000 miles. I was driving around recently and noticed the engine get really loud, and oil pressure go to zero. Here’s what I did to troubleshoot:
-changed out the filter and oil, no obvious obstruction or damage (i.e., bearing flakes)
-changed the oil pressure sensor to ensure it wasn’t a sensor failure.
-pulled the distributor and checked on the oil pump driveshaft. It was down in the little boss of the block and I stuck a hose down onto and attempted to pull up. It had approx. 0.5” of vertical play but appeared to be held in place by the washer clip. Based on it being captured like this, I assume that means the hex pump shaft is intact, right?

Questions:
1) Based on the above, is a broken oil pump the next logical cause? Any way to “test” the oil pump?
2) Should I pull a valve cover and crank the engine to verify for sure no oil pressure?
3) If I do have to replace the pump, can this be done with the engine in situ and pulling the pan (4WD bronco)? I’ve heard others say it’s easier to just pull the engine (is there at least an intermediate solution of unbolting mounts and jacking the motor?).

Thanks in advance.
-Alex