I am new to Inform7 myself but am building a game with a similar idea: the player is one of the NPCs (and in fact can switch between NPCs.) The example “Terror of the Sierra Madre” does something like this. Although I ran across some issues on descriptions etc. An interesting thread is Role-based interactive.
In my own game I now use a different approach since I want all NPCs to be handled identically. Then it would translate into something like:
Bridge is a room.
Captain Jon is a man in the bridge. The description of Captain Jon is "[if the player is Jon]You are Captain Jon[otherwise]Captain Jon is here."
When play begins:
now the player is Captain Jon;
now yourself is nowhere;