Lets take this one step at a time.
You virtualized your physical server. Did you p2v it or just spin up a new vm instance?
If you were to power off your vm, power up your old fog server at the correct address would everything be golden?
I assume your fog server is at HQ and your storage node is at a remote location. Does pxe booting a target computer at the HQ site work and the remote site fail?
And just to restate the obvious you disabled the firewall on the new FOG server.
The error (PXE-E11: ARP timeout) translated comes to the pxe client saying "Hey who has ip address <ip address of what is in option 66> send me your mac address, yet no one replied.