Opnsense and PFsense run on top of BSD underpinnings, so as long as the base OS sports the hardware you should be ok there, but:

I still don't really recommend throwing it all on one device. At the minimum, it's unlikely that a white-box PC with a wifi card is going to be as good for signal etc as a multi-antenna wireless device in hardware designed for such.

DD-WRT and OpenWRT can both do VLAN's and per-interface routing, so what I'd recommend instead is having AP's that run that software connected to port(s) or a VLAN intended for your wireless network, then having that run through your firewall (running PFsense, opnsense or whatever). You can even bind a specific SSID to a VLAN and separate your internal vs guest networks so they can't talk to each other (or at least, not without rules on the firewall host). That also allows you to run a bit of cable and space out multiple AP's in such a way that it provides better coverage, while still managing rules/routing/DHCP/etc so the central firewall.