Yes, FAST Cache is supported for Celerra storage also. There is a FAST Cache whitepaper on Powerlink about this feature: EMC CLARiiON, Celerra Unified, and VNX FAST Cache. 
Does Fast Cache support iSCSI LUNs (or filesystems that contain iSCSI targets) that are being presented via the Data Movers?  If so, is there a whitepaper?  I can't find it if it exists.  Thanks, Eric
Celerra iSCSI and FAST Cache