Thai Airways was notorious for releasing two seats at a time in business and first class. With US Airways, I have not seen this happen. So for the moment assume there is only a single seat left. And that you are hoping for someone to cancel their award seat and for the flight to be wide open enough that the cancelled seat would go back into the award bucket category.
To be safe, if you are not happy about the redeposit fee - if I were you, I would consider grabbing the single award seat just now, only if there were at least 50% of the seats in J currently open. The more J fills up, the less likely the chances that someone's cancelled award seat will go into that same fare bucket...