Anything could happen if marketing changed their mind.

Not only backfills. They can cancel posted vacancies if they want to.
Right up to the time they publish the awards they can pretty much massage the numbers however they want.
Seems like they've been leaving at least some "contingent vacancies" unfilled on almost every bid lately. That's their preferred method for shrinking a category without giving anybody the benefits you get under a mandatory displacement.

The only thing they can't do is create new vacancies without posting them. That would require a new AE.