Pavane, I use MusicTime Deluxe 3.0 by Passport, which does many of these things. Not sure what you mean on #9 and #11.

1. -yes- Which abc software supports multiple voices (in, play, and out)
2. -yes- Which abc software transposes Chord Names as well as the notes
3. -yes- Which abc software provides MIDI output
4. -suggests chords- Which abc (or other) package can add chords to a melody
5. -no-   Which abc (or other) package can generate realistic random tunes
6. -I think so. Can take in midi- Which packages provide input from a MIDI keyboard
7. -yes- Which packages allow aligned lyrics
8. -yes- Ditto, on more than one voice
9. -what?- Which software provides automatic beaming of notes
10. -yes- Does any other software provide tune structure audit (Check bar lengths against time signature.
11. -what?- Which software can play tunes according to the part specification
12. -no- Are there packages which can provide a harmony voice at a fixed interval above or below the melody?
13. -no- Do any ABC packages provide a percussion voice
14. -no- Do any other packages translate abc to tonic sol-fa