help with a best anonymity setup for galaxy note (or any android device I guess)

Ok, so I have a galaxy note and I don't want att to know what I'm doing on the phone. I'm thinking of rooting the device and installing an OpenVPN (Mullvad or similar). I figure that will protect my data connection. Beyond that though, does anyone know if att installs hidden software on android that gives them access to either the contents or activity on the phone? I'm thinking keylogging and snapshots at the worst, and maybe just logs of what apps I use and the like at the least. Call me paranoid but I don't trust these phone companies. Furthermore, I don't want any websites or services to know that I'm using a phone, is there a way to accomplish this?

On the other end of things I'm thinking of doing full disk encryption and installing droidwall. For phone calling I don't plan to use that part of the ATT network at all and want to do all my phone calls on a separate VOIP phone number, perhaps through NetTalk. What do people think? I figure going through the VPN I'm safe and ATT won't even know I'm doing it. Redphone and TextSecure are appealing but they only protect the _content_ of your communications, I don't want big brother or ATT or any other snoops logging _who_ I'm calling either. Suggestions?

Thanks.

Addition: Also I figure I should just download all the apps I need then disconnect the device from a google account to avoid any digital fingerprinting they might do.