Unique player spawning with networking

So I've been working on a little demo. I've got a lobby system similar to Warcraft 3 where you connect into a lobby and can chat, and the host starts the game with the "start" button. I currently have level loading working for 2 players.

However, I want the players to be able to choose their characters (much like a race in a RTS) prior to starting the game. How would I go about spawning a specific character to be controlled by that specific client?

In my current demo, I am sending a message to a game object (spawn) after loading is completed. It contains a script that instantiates a new player prefab. I'm thinking I can't use Network.Instantiate here, though, and I have to allocate the IDs myself? How can I get those to match up with the players' decisions in the lobby?

Any ideas would be great. Thanks! Let me know if I need to provide any more information.