Settings that can be changed on Xfinity gateway

I've been using my own Netgear modem/router, but I'm thinking of switching to one provided by Xfinity. How locked down are the router firmware settings? I want to be able to do things like:

- Turn off WPS

- Change channels and frequency

- Change SSID and password

- Configure custom firewall rules

- Change wireless encryption type

- Change router login

- Add a switch, hardware firewall, or AP

- Potentially set up port forwarding (although if not, this isn't a dealbreaker)

Can I do this on a router rented from Xfinity or do they lock these settings down?