Hi,
PALCE16V6, PALCE20V8, PALCE22V10 and GAL16V8,GAL20V8, GAL22V10 are fully JEDEC compatible.
I don't have any official proof from vendors but I didn't have any bad experience.
I think that in the past were compatibility problems with old AMD PALCE devices. These devices didn't have pull-up's on pins.
Lattice bought PLD devices from AMD and now PALCE and GAL devices are under Lattice.
I am not sure for ATMEL PLDs but I think that ATMEL use same architecture as Lattice.