There is no rule limit to the number of chapters in a story. It ends when someone writes a closing chapter, but it needs to have at least 3 chapters before it can be closed.
The prime source is part of the world. It is currently active in the story in which it was discovered. If nobody writes about it, then whenever the story closes, all creations etc that are active inside it automatically become available again.
And yes, in the final version of the game, you can't just vote no without giving a reason, so abuse will be quite obvious.
