leeneia,
if you wish, you can email the MIDIs to me and I can put them up on Joe's site, then link them here (and in corresponding threads, if they exist). I still mean to convert your JCA MIDIs to ABC and post them here, just haven't gotten around to it yet, though the MIDIs do import well into my ABC notation program—half the battle won.

You weren't mistaken in calling the C-clef the alto clef (aka viola clef). The center of the alto clef identifies middle C, just as the curl of the treble clef identifies the G above middle C. Its usual placement is on the center line of the staff, causing notes to sound seven diatonic intervals (a major seventh) lower than the same positional notes on a treble staff. That's because there's a five diatonic note interval from G to C, and a two diatonic note interval between the clef positioning lines.

Technically it's mistaken to say notes are sung an octave lower than written (as when tenor parts are notated with a treble clef lacking the octave appendage, or guitar parts are written on a treble staff); rather, everything is sung or played precisely as notated, in direct relation to middle C. However, I'm sure that was just an infelicity of expression, and what you meant was that the written notes sound (nearly) an octave lower than on a treble staff.