To partly answer Mr. Wineburgh's request, the first two tunes are well
known to me.  The first tune, by Mozart, I played at a young age when
taking piano lessons. It is the "Minuet" from Don Giovanni which has
been a very popular tune used in many piano teaching method books.

The second tune is a song from the 19th century English composer
Frederick Crouch.  The tune is called "Kathleen Mavourneen".

As for the third one, I can't hear all the notes clearly, I guess.
I see the teeth being moved on the comb but the notes are not all
sounding so I can't really figure out what it is.

Gilles Chouinard
Laval, Quebec, Canada