Hmmm....squeaking, but like something hitting in rotation at idle. Not coming from the belt. Maybe an alternator bearing going out? - That might explain the stall and the dimming too. But you should be able to hear it pretty clearly at the alternator if it is.
An exhaust leak between the manifold and cylinder head can make a squeaking, ticking kind of noise.
To see if the noise is coming from something driven by the belt, remove the belt and start the engine. Don't run it for more than 30 seconds or so - you will have no alternator and no water pump.
Belts squeal when they slip. And when they slip they become glazed, and sometimes leave crumbs of rubber near the pulley they are slipping on. Sometimes a new tensioner is needed, other times a driven appliance is turning too hard because of a bad bearing or damaged internal parts.
Take a good look and listen in the daylight.