I once had a couple of old, very small hair dryers, the old-fashioned
type with the skull cap and the hose.  I reversed the motors, built
enclosures and mounted them each on an equalizer with flap valves on a
old Cable "inner player".  In "Play" both motors ran, in "Rewind" only
one motor ran.

This piano is in New Madrid, Missouri, and to the best of my knowledge
it is still working.  The motors run very quietly.  So my question is,
why not install two "mini" suction boxes?

Regarding the pumping pedals working, the first thing that comes to mind
is a gear unit from an old motorized exercise pedal-bike.  If I recall
there was a device built in the 1920's that operated the pedals.

Andy Taylor