I solved it! After dinner and a show, I reviewed my work, again, and discovered a wiring error to the enclosed stereo out jack.
In my ignorance, I thought that as long as I correctly wired the sleeve, then which of the remaining two jack terminals didn’t matter for the tip wire. So today I learned that it does indeed matter!
Now I can go to bed tonight having learned how to populate a circuit board. How to desolder with solder wick. And, how to do some basic troubleshooting! I call that a good day!