When the GraphTech saddles are available, you'll be able to add piezo functionality to an original
Floyd Rose. I doubt GraphTech (or anyone else) will be making replacement saddles for a specialized trem as the ZR.
You would need to add a whole separate circuit to your guitar to control the piezo independent of the magnetic pickups. Piezos need a high-quality preamp to bring the signal up to a useful level, and you'll only really get the full impact of piezos by running their signal to a dedicated full-range acoustic amplifier or PA system (or direct to the board for recording). Piezos run into regular guitar amps aren't terribly inspiring.