1) where is the oil spot?
center, drivers side, passenger side?
Sides would indicate valve covers
Center front or rear would be main seals but oil loss would be much higher
Valve cover gaskets leak on the low side toward the rear, that is where oil collects when driving.
1a) fan belt squeaks usually start and then continue because of Glazing on the pulleys, glazing comes from the first slips of the belt.
Check tensioner, should be hard to pull it back to release and remove belt.
Then with belt off the pulleys, use some Emory cloth or fine sand paper to scuff up the pulleys, pay attention to shiny spots that's glazing
Belt works by friction, like tires on the road do, glazing is like ice, slippery, lol.
Wet or dry belt shouldn't slip, unless an accessory bearing is starting to go out.
2) not sure on the noise could be air filter and intake noise.
Could be fan clutch is starting to go out, and fan is "bitting" more air at high RPMs
3) the Cam Syncro housing on the 3.0l engines is a known problem, and between 80k and 100k miles is recommended change period.
The bushings wear out and they can start to squeal, high pitch noise.
Never heard of one seizing up BUT......it does drive the oil pump, so if it were to fail completely oil pump would stop, engine damage would occur.
There are a few videos out there on how to replace it and this: Ford Ranger 3.0L Camshaft Position Sensor
Best thing to do is to get engine lined up at TDC FIRST, then remove and replace in the same spot