User blog comment:Miskos3/Fairy Tail Episode 236: Tartaros arc Prologue: The White Inheritance, Review/@comment-2214433-20150607144722/@comment-7418318-20150607151033

Sting and Rogue only show up in 405... with the current episode dealing with chapter 361 that's still 44 chapter in the future.

Going by the usual rule of thumb that'd mean 22 episodes, which would be something around 5 entire month.

So either they made those scenes specifically for the trailer, it's only a cut of concept art or it's fake.

My guess goes to the middle one.