Don't worry if you poach and the return goes a different direction, the server should be covering where you would have been. The unwritten rule is, if you have a floater of a return that you can kill, then kill it, whether you planned to poach or not. Your partner should understand. In this service formation, the idle player on the serving team stands nearer to the center of the court. It can make poaching in either direction easier, but it is only appropriate for a team that is very familiar with each other, as it is a faster and more unpredictable way to play.
Doubles can get messy and fast, especially when all four players are at the net.
You can never call too many shots. Sometimes one player will take a shot that seems to belong to another player. This is okay if it is for tactical purposes. It is not okay if it is a friendly game, and one player is taking all the shots. Retreat, unless you're running down a lob.