Regarding employees -- I would suggest something.
Find a Star Wars game with unreleased prequel music... Then track down the individual responsible for the music on facebook, another homepage, etc. and ask them if they had any. If you think this is futile, it is not.
I wanted to track down as much information a series of videogames for my website at one time so that it could contain as much information about the world as possible. I went through EVERY single person in the credits to each game and tracked down each one individually (if possible) and asked them if they had anything left over from working ont he game. This was EXTREMELY fruitful. I ended up with much more than I ever expected -- I got complete verions of design documents, the actual 3d files used for many places in the games, many beta screenshots, hi-resolution videos (higher than the in-game quality), correspondenses bewteen team members, production artwork etc... (though I acquired different things from different people).
Just thought I would encourage something to take the time to at least try.