I have now successfully implemented the following

Keyboard input 0 = double note, 1 = full note, down to 6 = 32nd note, 7=grace note. (Harmony does not support notes shorter than 32nd)

. = dotted toggle (I could add D for the same thing)
M (Measure) = insert bar line

Bar lines are necessary because the score function uses them to force line breaks. If you don't have any, the notes will pile up on the right of the screen! I must fix that sometime.

Tuples: select n consecutive notes (where n in range 2 to 5), and click the icon. The program will convert to an n-tuple (or Unconvert, if the group is already a tuple)

I hadn't thought as far ahead as adding chords and lyrics at the same time, but there is no reason why I couldn't.