Re: IP Pools and Zones
First, FGT's zone is just an "alias" to represent multiple interfaces with one name in policies. Nothing more than that, which is different from Palo Alto's zone, or Juniper SRX's zone, or some other server vased FWs as far as I know.
Then SNAT with ippool shouldn't be affected if you use interfaces or zones for src/dst interfaces in policies. As a matter of fact we use zone for an outing interface on one of our FGTs while SNAT/ippool is applied to the policies.
Is it not working?
Of course if there is returning traffic toward the SNAT IP from the destination side, there needs to be a route on the other end to point the traffic destined to the SNAT IP to the real interface.