“The plan was, take a
catchy tune by some pop composer like, oh, say Mozart, and attach the alphabet to it.”
Was the tune that we now know as the alphabet song really written by Mozart? That’s pretty cool. What is it’s true name?
The link to the Mailbag article: Why do the British pronounce the letter zee “zed”?
… and I think it was Haydn, rather than Mozart.
Mozart composed the tune for 'Twinkle Twinkle Little Star," didn’t he?
Well, actually it was a traditional (anonymous) French Song, “Ah vous dirai-je maman.” It was popularized in Mozart’s piano tune (K265, 1778) “12 Variations on ‘Ah! Vous dirai-je, Maman’”. Check out http://midiworld.com/cmc/mozart.html , and go down to “Variations on …” to hear Herr Mozart’s arrangement.
As I mentioned in another thread on the site, one of the Bach family also did some variations on the French tune, easily playable by anyone with about 3 or 4 years of lessons under their belt, and quite fun to listen to. 
It is also quoted in Saint-Saens “Carnival of the Animals” - movement “The Fossils”. Even then it was a very old tune. All of the notes I’ve seen reference the French, rather than the English version.
Having read the article, what do Brits call cookies? Is it biscuits?
Cooper asks:
> Having read the article, what do Brits
> call cookies? Is it biscuits?
“Biscuits” in British English can mean either cookies or crackers in American English. If you want to distinguish them, you could say “sweet biscuits” or “savory biscuits” (except that they would spell it “savoury biscuits”).