Your hints are always appreciated, Malone. I have been thinking a lot more about this puzzle, probably too much. For quite a while I had
R-E-D---I-N-G on the theme line and it occurred to me it might represent Red Herring. I also had Frank and was looking for Sinatra or JR.
I wonder if these red herrings were deliberate, if so, clever. I did not understand the "key variation" point, but am not familiar with this music
Lovely puzzle and a nice tribute