Multiplayer Position Sychronization problem in unity2d

I want to make 2D Game which is something similar to “Funrun”, I have some issues in it,

  *  Platform: - Clarity is not proper & Polygon Coliider is not properly working.

  *  Character collider is not properly working..

  *  Multiplayer: -
              -  Synching all players position is not working properly.
              -  Game performance in multiplayer is .
              -  Starts game after all player's are instantiated.
              -  identifying each player-tag/name on head.
              -  How can i add friends using fb.-Not yet Implemented, needs suggestion about its implementation.
              -  How can i Chat with freinds.-Not yet Implemented, needs suggestion about its implementation.

I have used Photon Multiplayer Plugins.
Please tell me any reference which will be helpful to me starting from scratch to apply muliplayer in 2D game .

Thanks in advance.

Because of lot of data to be send over network, it causes problem, so it is better to send minimum data, and sync position in fixedupdate if using physics.

If have better solution , then just share it…