Multiplayer-Spawn pawn/char, possess it

  1. Spawn the horse.
  2. Possess the horse. This automatically Un-possesses the character, without necessarily destroying him.
  3. Attach the Character to the horse. You can do this any way you want. I would try it with a socket.
  4. Your character is now attached to a horse pawn which is controlled by the controller that used to be controlling the character. I.e. the character is now riding the horse.