1. AT&T will give you a router with wireless access point. I don't know about everywhere but here it is a cheap poor quality Belkin, I think everything Belkin makes is horrible, we're on our third one in 14 months. Anyhow, you can put whatever WAP or router you want on the LAN but forgetaboutit if you used a site to site VPN in the past.

3. Not a problem, but if you use the Belkin wireless heavily expect it to burn out in 6 months. 

4. You can turn off the wireless on the equipment AT&T puts in, use your own WAPs.

5. No problem, the UVerse box converts your voice back to POTS.

6. Good luck with that. And if you were like me and used a router, such as a Cisco ASA to maintain site to site VPN connections forget about doing that now. I begged to put in my own modem, nope {Content Removed:Keep it Appropriate} they say, you can't touch a public IP address. Now I have to run VPN client on whatever I'm on at the moment and it is a PITA.