I included only Damon because in the promo of 6.05 we see Damon in a scene with a light while Bonnie not. So maybe Damon will come back but Bonnie not?? Possible or not, i don't know.

6.05 - The title is a hint itself maybe? "Damon and Bonnie make an important discovery that affects their quest to get back home."

6.06 - "Damon is determined to take matters into his own hands when he receives some upsetting news."
PS. Ian posted a photo filming in the street for this episode, while in the promo pics Elena, Caroline, Alaric...are there too.

6.07 - "When the past comes back to haunt her, Elena is forced to face her problems head on."
"Damon stumbles upon a startling clue that renews his hope." "Kat Graham also stars."

It has to be 1 of this episode. 6.08 is directed by Joshua Butler and we know that DE scenes exist and probably not flashbacks. At least to me, it did not seem as flashback.

You might want to mark this as a spoiler. I think Damon will transported out at the end of 6x05 and be back in 6x06. And I think Elena might get her memories back in 6x07.

^ Sure but i think the question itself is not a spoiler. My comment maybe yes but it's just a speculation and everything the synopsis say....

:)