I think that Orlando's, out of the three, will least likely occur because SWO is the one that needs it the least. San Diego needs it the most although San Antonio is most likely to happen because it was already announced that San Antonio would get a new coaster in 2017.
So in order is most likely to least likely:
1. San Diego SeaWorld Rescue dark ride
2. San Antonio SeaWorld Rescue launch coaster
3. Orlando SeaWorld Rescue dark ride