"12 beats" makes no sense, they're talking about melodic phrases of 12 notes or less. You can also have a same sequence of notes, but different rhythms or starting on different beats and it'll sound totally different. And then there's the non-diatonic, or borrowed chords - doesn't even take into account Lydian or Mixolydian mode. I dunno, first pop melody that comes to mind that is an example, Michael Buble's "la la la" line in "Everything" is not in this collection.

Also, for actual complete melodies, I'm not even sure Happy Birthday would fit their restrictions. It's diatonic and within an octave, but the range is from V to V rather than I to I. So if they're assuming I to I, it wouldn't fit unless they supported mixolydian mode.