There is also ICMP ping between members of cluster for lowest / highest VLAN checking.
What about DHCP ? udp_67, udp_68 ? Communication for DHCP server / Client.
In case backups from GW or SC are set, relevant ports are ftp, ssh (scp), tfp towards backup server / management.
Access to GUI DashBoard is done via CPMI and access to CMA / SMS via GuiDBedit is done via tcp_18190. (maybe you can add PC at very left, it will represent end user PC with SmartConsole installed)
Not sure if IGMP is relevant here, but this is also passing between GW nodes.
PS: The legend field (in purple) at the bottom of the drawing is not visible at all. Looks it is just picture inserted ?

Kind regards,
Jozko Mrkvicka