I have created a custom poller for Fortigates to be natively support by 10.7 when you select the resources.
To import this navigate to Settings > Manage Pollers > Import
Hope you find this useful.
Also if anyone is able to get one working for units that work in HA that would be great, I am currently struggling alot to get this working as the Multi processor option for these pollers still expect a single value for MEMORY when you would expect to recieve two for HA.
All the best