You can posses only one pawn per player. They all are also on separate pcs (or in separate engine instances).
So you should reserve pawn and player controller for actual player.
Make pawn that is only flying camera. That can update its location and rotation from real player controller over neetwork.
Use those camera pawns to display viewports on monitors.
Not sure if dispatchers work over network but if they do they are best for this task of updating locations.