What happens to the content if the Publication lease isn't renewed?
In the case of a Publication that is canceled or not renewed the content reverts back to the writer. The writer is then free to resubmit to another publication if he/she is a writer for one, or publish it to his or her Personal Journal if they wish. The writer can also change the Niches that the content is associated with if they desire to do so.
I see that our FAQ about Publication cancellation doesn't address the content, but it should. I'll add it in this morning.