Hi @sianand,
welcome to the forum!
technically your scheme can work for most applications but it may be quite complex to manage it. All difficulty depends on your inbound/outbound balancing requirements.
If I were you, I would consider those topology alternatives:
-
Use firewall of Peplink router without additional security appliance.
-
If intermediate firewall is necessary, check option of:
A. Firewall in L3 NAT mode + Peplink router with advanced feature Drop-in mode
B. Firewall in L2 bridge mode if possible.
Best Regards