No, the HA pair doesn't look fine, it's non-functional.
Why are the HA ports orange and not green? What does a mouse-over tell you?
Be sure all HA parameters except for "HA priority" are identical (group name, password, group-ID, port settings). Do not use port monitoring for now.
All HA heartbeat ports are connected 1:1 (port 9 to port 9, for example), with straight-through cables.
You need to have a green sync status, or the cluster has failed to form.
You will see a lot of information if you connect a PC to the serial console port.
"diag debug enable"
"diag debug app haproxy -1"
to get HA diags.
What will prevent cluster formation is
- using DHCP on any interface
- using PPPoE on any interface
- using different firmware versions (incl. patch level) on cluster members
- widely different time settings on both members
Rather than watching a (fast-paced) video, I prefer reading the recipe (or the corresponding chapter in the Admin Guide, to understand how HA clustering works): https://cookbook.fortinet.com/high-availability-two-fortigates/
You can connect to a mgmt port to manage a FGT (as long as it's got a static IP address, or offers DHCP). You need to allow HTTPS or ssh on that port. But, routing will not work on a mgmt port.