You can retrofit an OFR arm to A ZR, and you can retrofit an OFR arm to an edge, so I would assume they are compatible.
Though in my opinion the original ZR arm is fantastic when its working properly. I believe a guy on the Ibanez forums manufactures some heavy duty replacements for the arm holder itself, I would look into getting one of those, since I find the ZR's 'no play whatsoever' arm holder to be great. Its just a shame the weak materials cause it to break or work itself loose over time.
----------------
Now playing on Winamp:
Pantera - Throes of Rejection
via
FoxyTunes