On the 1st part yes we deployed the VM for a demo . On the 2nd part(s0; no, I don't recall ever FTNT and MS ever getting to agreement for other FTNT products in the azure cloud solution.We use the real manager-appliance & with a tunnel from our real DC to the vCloud and it worked fine btw.
If you need to manage other FGTfws and have an existing manager than it just simpler to run the virt-instance across a tunnel back to corp at the real or virtual appliance be done. No need to install it a remote-cloud unless that's your only datacenter.
As far as Virt-FWAppliance it worked fine but we had issues within the memory allocation that support never figured out. Our pass lame SSE team also never completed the POC so we dropped the whole azure and FTNT solution & abandon the case with support so I can't comment if the appliance was the issue or azure but as far as my understanding the image in the azure mktplace is the exact same image anywhere else so it should just work.
IMHO: I would strike up a license and roll out a POC before getting fully involved.