I'm having exactly the same issue. Both apps (sonarr and radar) are tunneled through the vpn as per console output, but wont connect on the webui.
I have tried adding the ports as you suggested, but for me nothing.
I'm Wondering if its something specific with the sab container, as he was using deluge. I may just try the openvpn container instead.
When adding the ports in the sab variable, did you also delete them in sonarr and radar, or did you leave them in?
*Sorted now, forgot to add the port in a new variable as well as add it to VPN_INPUT_PORTS.*