Where's the super simple "I just want to setup pfsense like a store bought wireless router" tutorial? Plug in to modem, setup the wifi SSID and PW, and I'm good to go?
A lot of people use pfSense precisely because it is not like a store-bought router. These ISP supplied or consumer grade devices are enough for the average user, but if you are familiar with DD-WRT I imagine you have greater requirements and more confidence in your skills than most home users.
I can't comment on out of date documentation without knowing which ones you read, but I would research this as two separate issues. One is setting up the wireless AP. Two is configuring an OPTx interface - whether or not OPT1 is a wireless interface should be irrelevant for most of it. I would remove the bridge (or start again from scratch if you are not too far in to configuring it already) and simply set up OPT1 as a separate network, and ensure your rules allow the appropriate traffic out (see my earlier post about default rules only for LAN).