Most people using their own router seem to put the T3200M into bridge mode - i.e. the Telus box is on the outside of their network. I'd like to use the T3200M as a simple switch and Wifi end point inside my network. So ...
I would run from the GPON to the PFSense device and then to the T3200M - and turn off all the firewall stuff on the T3200M. I'm assuming that I will have to allow the PFSense device to pass all the protocols etc for OptikTV, perhaps an external IP for the T3200M.
There are some individuals that have been using pfsense with varying degrees of success depending on what they are trying to accomplish on their home network. One huge thing you will need to be aware of is that with any non-Telus network setup, tech support will not be able to offer troubleshooting for any problems you may encounter with Telus services like Optik. If a tech has to come out to try fix a problem, they won't support third party networking hardware or configurations and will typically disconnect any non Telus equipment and see if things work in the default supported configuration. There is also a limit on how many public IPs you will be able to use. The T3200M is not designed to be used strictly as a switch + wireless. You can bridge port 1 though.
What I do is plug a switch into the ONT, one port on the switch goes to my router and another goes to my T3200M, Wifi is disabled on the T3200M and I just hardware my Optik TV boxes over Ethernet. I don't watch TV, the family does.