landing gear on a fazer

[Sunny Intervals]

I would say electric has to be the way to go.
pneumatics will need a store of air, so a reserve tank, way of charging the tank compressor and associated PTO from engine/gearbox to drive compressor , condenser/air dryer,
And that's before you start work on the legs.

If you do go pneumatic route will you be going with air pressure forcing against spring pressure to lower the legs, kinda like truck spring brakes where air pressure holds brakes off, so if there is an air failure  the brakes are applied, or in your case air failure raises the leg.
or air actuation in both directions.
Spring pressure dropping legs if there's an air failure, I haven't decided if it is a bad of good thing yet may be good if the spring is sufficiently soft to allow bike to lean into bend without tripping it up.
The geometry of the wheel and leg would have to take into account the possibility of drop at different angles of lean.
But then again soft spring pressure may not be enough to support bike and rider

I'm just thinking out loud  :\
Lot of stuff to think about, I wish you luck