American-ish Chorale Tune | © Study: Paul Simon, Bach, Hassler | Schola Diffusa | Virtual Choir

In this choral meditation on copyright. "American-ish Chorale Tune" mashes up Paul Simon, who copied from Bach, who copied from Hassler, who copied from minstrels.

Who is this piece's "composer"? Who owns the copyright?

Some study notes:
https://docs.google.com/document/d/1d...

As a percentage, how would you allot this song's creative contributions?
From medieval German folk song (Melody — 1500s — Public Domain)
From Hassler? (Melody — 1600 — Public Domain)
From Bach? (Harmonies — 1727 — Public Domain)
From Simon? (Lyrics + Embellishments — 1972)
...For melody? Even though just fitting folksong/Hassler/Bach to his lyrics?
From tmarkjames [Musescore user] (Mashup) https://musescore.com/user/32959326/s...
...who gave the mashup CC0 status
From Riehl? (Artistic modifications + Additional Harmonizations + Embellishments + Audio Editing + Video Editing — 2022)
From Soloists? (Embellishments + Performance)
From Choir members? (Performance)

Who owns copyright in the song? What percentage of the whole?
Hassler — Derivative Work?
Bach — Derivative Work?
Simon — Derivative Work?
tmarkjames (Musescore contributor) — Derivative Work?
Could tmarkjames actually disclaim copyright — under CC0?
Musescore (distributor)
Riehl — Derivative Work?
Singers?
What jurisdiction applies — since singers sang from Russia, Australia, U.S., and Spain?

Who should get paid for this?
What percentage?

Should YouTube be able to demonetize it — with Simon getting 100% of the royalties?
YouTube says that this song uses Simon's "melody" — which is properly in the Public Domain (i.e., Bach, Hassler, 1500s minstrels).
Is Simon the 100% songwriter?
...to the exclusion of Hassler + Bach + tmarkjames + Riehl?
Fair Use? As Copyright criticism?
Should I be able to dispute — without risking a "three strikes" death penalty?
Even if not fair use, shouldn't I be able to share royalties with Paul Simon — as a derivative work?
How would I do that?

Should Simon be able to sue Schola Diffusa?
If so, who has infringed his copyright?
tmarkjames?
Musescore?
Riehl?
Singers?
YouTube?
IF SO, what damages? Full $200,000+?

What does all of the above say about our copyright system?
How many choirs (usually schools/nonprofits) would attempt this piece?
Or instead, for fear of $200k+ penalties, just avoid it — to be "less risky"?
Does the above — and reduced musical output — "promote the progress of science and useful arts"?
Is the above "fair" and "just"?
Or should everyone involved just be able to create art/beauty — as Hassler, Bach, and Simon did?