So squealing will get louder with engine speed. And the tachometer will not respond while it’s squealing. Then when the squealing stops, tachometer will kick on. The two issues are completely synchronized.

So I’m guessing alternator (original) related. Perhaps the pulley? Seems like the pulley is spinning freely and not turning the alternator.

Not having any battery issues yet.

Thanks in advance.

 

Alternator related would be my guess as well, although I've never heard an alternator "squeal" as you describe. Imagine if you pop the hood and visualize the alternator pulley would be able to tell if it was spinning?
I've found a good pair of mechanics ears/stethoscope to be invaluable in diagnosing serpentine related noises (and all kinds of noises...).
If it is the alternator I'd avoid any long trips before you get it sorted out...

 

There's a small wire out the back of the alternator that provides the signal to the tachometer. If the belt slips on the alternator pulley, it will squeal. There is extra force at the alternator pulley right after starting as the battery gets recharged, especially if the battery is on it's way out.

Parts stores have pretty good free tests to check batteries and alternators. That's where I would go.