Fantasmic! will definitely not be going anywhere. Word is that there will be some enhancements to the DL version of the show when it comes back from Hiatus next year and it wouldn't surprise me if F! went down at DHS to implement some of those enhancements, however I doubt they would do it when the park is stretched for capacity as it is, so I think it will be much further down the road.
WDW has not been releasing their schedules too far in advance lately. I think we have to accept that we are in a state of flux when it comes to this stuff. Hopefully they will get everything smoothed out and more stable soon and can get back to some predictability.