Serpentine belt keeps shredding (I have been

most likely the idler pulleys ,any chirping or squally noise take the belt off and spin all the pulleys to check for seized components. Also double check routing for protruding bolts or bracket that might rub the belt

Your belt doesn't have enough tension to turn the starter enough to start,replace belt .

Sounds like one of the pulleys is not aligned with the rest. You can use a straight edge to check the alignment.
I would also want to make sure all of the pulleys are secure and not loose or bent.

you need to wire brush your pulleys so all grooves are clean and see if one of your engine components that run off the belt are loose or have a bad bearing good luck

I would look online for a diagram on how the belt is to be run around the pulleys to make sure you are running it correctly , let me asked you this is this what it did to the original belt if not it is not run correctly over the pulleys ?

take the belt off and carefully check to see if any of the pulleys are out of line and check to make sure they spin smooth and true check for bearing wear and noise in any of the pulleys cause it sounds like simply there is a pulley out of line

is the a/c working ok??? shredding the belt may be cause by the a/c compressor problems. the "chunk" maybe not, but shredding tells me something does not spin when it should. I dont know why the mehanic put a new pump on that had a problem with the pulley, it should be smooth. anyhting that the belt runs should be smooth and east to turn, make sure that all of the grooves are clean, no remnants of the old belt.

Well there's only part that has to do with the cooling system and serp belt - the water pump!! Maybe it's starting to seize or has too much play. Either way, when you change the water pump, replace the thermostat and flush the system very thoroughly, those 98-99's are notorious for rust build up. Make sure to pull the heater hoses off and flush the heater core too. After all said is done, purge the coolant and make sure there is heat from the blower. If not you're going to have to replace the heater core because that gets clogged sometimes when flushing.

PULLEY ALIGNMENT.WITH BELT ON LOOK AT THE PULLEYS FROM THE SIDE.U MUST HAVE A PULLEY THE IS MISSALIGNED