Well, I've never heard of a 511, so I can't answer. Closest I know of is 501, 510, and 521. Generally, yes, the remotes can be set to different addresses (your User Manual is your Friend). All Dish receivers that are online will automatically download current firmware as long as you don't set the option to prevent it.
As for using a wireless A/V repeater, yes that will work, but another solution is to use diplexers to send the TV signal up the wire to near the existing bedroom feed and tap it off there. The installer that does the second satellite feed to the livingroom SHOULD know how to do this.