Personally, I think it is a great idea. But run it past tookArook for his input.
I like method 2 the best, run on the honor system.
Because of my current work load, however, I wouldn't be able to moderate it, so you'd have to find a moderator or do it yourself.
Amy
Playing here, there are many different possible ways to do it:
Of course method 1 will be the only real true team-game as it should be, but the discussion by email makes it long time using.
This should be only a game for fun and (hopefully) also promote shogi.
Method 2 is very close to 1 with the only difference, that no one can really proof that nobody is reading the thread of the opponents.
(Maybe only possible, if chess.com is supporting threats, where only invited people of the thread-opener can read.)
But again, it's only for fun.
So maybe I would prefer method 3.
Still it's a little bit strange, because you should not post all your secrets (like "... and if they make this move, we can mate in that way ...").
But on the other side, maybe we all can learn in this game, because it's NOT this way, that your opponent will be surprised by a fatal mistake.
What do you think about it???
So I would do it in the following way:
And when it's time to move is reached, the team-leader makes the move corresponding to this open (!) discussion.