1. No problem here.

2. Then you'd know how many ships etc I have. You might then see me use most of them in an attack and you suddenly know I'm weak where you'd like to attack! Doesn't appeal to me.

3. In-game messages are already allowed! Either to everyone or to single players. So limited diplomacy is within the game parameters. You are not permitted to coordinate action, agree NAP's etc. You are only asked not to communicate outside the game ("Communications between players outside of the game is not banned but it is discouraged."). Not readily checked, but if you start acting as though you were receiving information you shouldn't have for example, the host would probably take exception.