So far as your questions go, idealist:
1) Don't post usernames, just countries. The game is anonymous, so usernames wouldn't be helpful anyway.
2) You're encouraged to pretend to be other countries. You can sign as your real country, too, though.
3) Feel free to say someone is lying, but don't start any post-wars over it. If you're commenting on a message, use the comments instead of a new post. Might be easier that way. There'll be a lot of communication already. I don't think we need spamming on top of that.
In general, lying is fun. Do it. The only things I don't want to see lied about are pause requests. Lying about draws is totally fine, though.
I'm looking forward to this game, too! If anyone's interested, but doesn't want to follow the blog, I'll post the blog when the game is done so you guys can see how it worked out.