1) The SWUs are still attached to the reservation/ticket, expired or not. AA's only rule is that you must clear the upgrade prior to expiration; travel can be after expiration.
2) You booked prior to expiration and cleared the upgrade. For all intents and purposes you are now holding a business class ticket. If they want to change their schedules, that's fine, however you are to be reaccommodated in business class for such involuntary changes.