Hadn't really thought about the match order in terms of deck posting, oops - but yes, the best idea seems to be not to post the General's deck until all matches with it have been completed.
If the General still has other matches left to play in the round, whether it's an EC match or a standard round match, he can simply make a placeholder post in the battle results section until all matches are finished, then go back and edit his posts before the round timer is up.
In the case of people passing intel to their teammates before EC matches happen... well, we can't stop this. We're not ever going to police every possible method of communication between you guys. We just have to leave this part to trust - telling your General what deck he'll be facing in the bonus match gives him an unfair advantage over his opponent - in the spirit of War, we just have to ask you guys not to do this, even if it does give a tactical advantage to your team.
Thanks for the positive comments on the event card so far, usually we only hear from you guys when things are going wrong, so it's nice to get some positive reinforcement.