If you've got five cams, having three up in front of the stage (especially in a venue this size) would be a waste. It's not likely they're going to get that great of a shot because that's the area to which security pays the most attention, and the fans will be knocking you around.
I've coordinated multi-cam stealth shots like this before. I'd do it this way:
1. one cam up front (and hope the guy can get a decent shot and not get busted)
2. two cams - one cam on each side of the stage (left/right - located somewhere around where the second pic from the top in your diagram was taken)
3. one in the back taking a static stage shot - get the full stage and just let the camera run.
4. one in the back taking a static shot of the big screen - zoom in to fill the screen - and then just let the camera run.
If someone is going to record audio, it should be one of the two guys in the back because they won't have their hands full with a camera.
Make sure everyone knows how to adjust the exposure on the cams - over-exposure will kill a good shot.