Worn Pulley Squeal with Symptoms

[lothian]

2006 Sonata
148k miles

And just like that, the typical sound of a worn idler pulley emerges from the car immediately after start up. It squeals for a couple minutes and goes away. We're all familiar that noise. Only a mild hassle, though 'cause it's a relatively easy job to swap out an idler pulley.

'cept here's the thing... it ain't the idler pulley.
while driving, the power steering and alternator will go out intermittently--presumably the A/C would also cut out at the same time, but it's chilly here presently. So what do these components have in common: the drive belt. That symptom, combined with the pulley squeal, lead me to believe the tensioner pulley--and not the idler pulley--is going bad. Pretty good sleuthing, eh?

'cept here's the thing... it ain't the tensioner pulley.
It seems the squeal is coming from the power steering pump. (Btw, the drive belt is in excellent condition and belt tension is nominal). My new theory: a bearing is failing within the power steering pump; the squealing disappears after friction warms it up a bit. But that doesn't explain why the alternator warning appears simultaneous to the power steering going out.

Thoughts? Opinions?