Never say never...but don't expect too much
I would say its highly unlikely we will see Lily Blossom or the complete Star Dreams set again or AJs truck. Hasbro may run out of ideas and include Star Dreams or Lily Blossom in a future release but normally in toy lines like this when a toy/set has been out and a wave has passed, essentially the toy is retired and will not be seen in the same way again. So for those, as Jinxxy says, ebay or the Arena is your best bet to track them down.
Fashion Style ponies are a little different. Hasbro clearly only intend to release the main characters in this style and they have already proven they are on a cycle for release. I would think we will see them repeated again.