Bill..
Keep in mind you can assign different foot switch functions for EACH registration. In a piano reg you might want one pedal for sustain and another for fill to self.

But, switch to guitar and you might want to assign what was the sustain pedal to Glide for a country or blues number.

As far as triggering Vocal Harmonies, on the 2000 I found the easiest way was just to use the VH button on the board.

Eddie