I'm betting that actor already knows. The show won't pick up a full option on someone just for one season, especially if it's a major character. That would eat a massive hole in their budget. Also, it would be INCREDIBLY bad business to make an actor wait another a full year of work (realize, this finale was shot six months ago plus another six months for the episode to air) to get another job.
reality is, one of these people will probably be cast in something in the next six months and that will tell us who died... which is another stupid reason to hold this cliffhanger over.
*cough*
http://deadline.com/2015/10/norman-reedus-biker-reality-series-ride-amc-the-walking-dead-1201597085/