OK,
FIXED!!!! This was easier than I imagined but have NO idea what caused it.

The beauty of having 2 of these pistols is that I removed the slide and grips from the functioning pistol and laid it next to the non-functioning one.
I
immediately noticed the trigger bar was further back on the "good" one about 1/4". Huh? How could that be? So I looked into the trigger and spring area of the "bad" pistol and saw ...... nothing. But something was keeping the trigger bar further forward on this pistol. So I took it apart (again

) and made sure everything was in its proper orientation and VOILA! it was now in a position 1/4" further back than before.
Perhaps during the spring replacement last night and my building frustration I did
something wrong? But what? I have absolutely NO idea as there are only 2 holes in the trigger. Put everything right, checked function and IT WORKED!!! I am fully convinced a family of gremlins inhabits my house!!!
But, bottom line: The new spring fixed the pistol and now it works, too. I am a happy boy!!! Sorry I couldn't give more detail on what I did to screw up this spring/trigger/trigger bar orientation that locked up the pistol so others could watch for it but maybe just keep in mind it's possible. Unless it's gremlins ....
EDITED TO ADD: I thought about this last night because it bothered me that I could have made this mistake yet could not figure what it was. There are obviously very few options for causing something to make the trigger bar not reach back as far as it should to engage, so I figure I must have put the rear post on the bar (the one the spring leg goes
over through the trigger hole and
then put the spring over it. Leaving the front post (the one that actually goes through the trigger hole) outta the hole and forward by itself unattached! I guess it could work and in my frustration (I'd been at it for hours...) and lighting was getting bad (it was getting late and dark) I guess I put the rear bar thru the trigger and THEN put the spring over it.
Now I do not know if this was the case but it kinda makes sense when you figure the trigger bar on the gun that wouldn't work was about 1/4" closer to the front of the gun than the trigger bar on the gun that was working fine. Space between the 2 posts on the trigger bar - one for the trigger "axle" and one for the spring to ride over is about 1/4" ....

So be careful if you get tired, frustrated and the lights starts to get low (even with a flashlight in your mouth). Or it could still be gremlins!

Hope this helps.