Is it actually possible without GT-MP involved? My tend is make it possible to add the regular single player animals to be synced with the server without having it need to take any player slots. The animals that are spawned as in single player that is, so there will be an option in the server config that loads the single player animals, birds and sea creatures.
Besides animals, is it also could be possible to be able to load overall single player bots? (vehicles, airplanes, people whatsoever)