There's 2 ways you can change your name now in TF2/DoD:S:
1. Change your steam name. You can do this by right clicking your name on the steam friends list and clicking set friends name. This will be the name you always use when you connect to any TF2/DoD:S server.
2. There's a command you can use by entering it into the console. I'm not to sure of the command, it's something like setplayerinfo name or setinfo name, maybe someone who actually knows it can post it, I'm just guessing, I've never used it, but if you use this command, you have to put this command into the console every map change to put your name back to the name you want, or make a macro.
Both games are now linked to the Steam name you use and can't be changed in the options in either game.
About the Multiplayer tab, not sure what you mean, I'd have to load the game to take a look.