F5 Positioning between 2 Firewalls (checkpoint and fortinet)

Is the return "load balanced" traffic not coming back to the F5?

Is the client traffic not hitting your FW1?

What is the default route on your FW2?

Is your FW2 a bridging or layer 3 firewall?

These are unknown variables to me. So any suggestions at this point could be invalid.

Wildcard VS? Are you talking about IP forwarding virtual servers? For example, when your real servers need to go to Microsoft or Linux or whatever vendors to get patched and the traffic has to pass through the F5, yes you would need an outbound IP forwarding virtual server. Same thing for inbound. If you want to get to a particular backend server behind your FW2 from your workstation, for example, in order to do some maintenance, install patches, software, etc., and you don't want to connect to a VS, sure you would also need an inbound IP forwarding virtual server. Just search for "IP forwarding virtual server".