According to the most recent Podcast from Disney, it was stated that while nothing official is being released, this small opening window may be pushed back further.
Evidently they are installing a fog system in part of the attraction and to do so they had to remove a large portion of a wall or something like that. They will not reopen the attraction (even temporarily) until the effect is placed and completed (since opening without completion will expose a large hole where the effect is to be place, where it will likely be concealed once completed).
Also, the effect, even though completed, will NOT be running when the attraction re-opens, and will run only after the full rehab is complete.