Hi,
--- first option
what you need is separate Input from players.
each Human player will be represented in your logic by a network object that is just taking the inputs, that's it.
then your game is instanciated various characters, that accepts inputs from these network object, and you will link them together dynamically, using RPC to call for a connecting like : player 1 input take controls of Character X
then, each instance across the network, can adjust to that.
your characters can be network instances too but as scene objects.
-------- second option
switch ownership. I assume you use Photon, in photon you can request ownership. and so you can change the owner basically. however this ca be tricky especially if players disconnects, if you are currently owning an object that was not yours, and if the original owner disconnects, that object disappear. you can however create just scene objects to solve that.
Bye,
Jean