I found it! Or rather I just stumbled across it, wasn't even looking for it, it just landed right in my lap. I mean, sure I know the song, but didn't make the connection; this is that ditty my dad would always fingerpick whenever he had his guitar in–hand.
And of all places, I found it by re–watching Intolerable Cruelty. 🤣 It's sung during the wedding scene, by the performer of the marriage ceremony, the guitar–picking and grinning "captain of the Good Ship Amore Veritas"... FATHER SCOTT.
I can NOT make this shit up! 🤣
One of the attendees at the wedding even looks dead–up like one of my dad's best friends, a guy I was just on the phone with exactly 12 hours ago! Whut tha fuck is going on?!?!
This all makes me supreeemely happy. It is too fucking awesome.
And hey, it is a lovely song, no doubt about it. I just, I had to write about this, I couldn't keep something like this to myself. It's got me me questioning reality, not whether it's real, but... it's like a Slaughterhouse Five kind of spacetime continuum–twisting moment. This many coincidences, in such pretzeled chronology...??? 
I see Lily Tomlin holding up a giant book titled Coincidences in I 🖤 Huckabees saying "They're not all significant," I reflect on the principles of randomosity and their assurance that lightning has to strike twice somewhere eventually, and I marinate in rich steamy soup of profound cosmic mystery, no matter what it's made of, I don't much care, the sauce is good. What a perfectly, comically divine singularity of a moment. Marvelous. Spectacular. My cerebral synapses sprout endless tendrils sprawling throughout the entire universe.

That whole Shangri-La's album is amazing. Hall of Fame record for me.