The FE that rewards the Ambassador could also be part of the 3rd Year Anniversary. In fact, it's very likely what the 3rd Year Anniversary will be centered around.
Not going to rule it out, but I'm really not expecting it.
The First Anniversary was just Q appearing and us fishing for goodies (literally).
The Second Anniversary was basically the same, with Q appearing and giving away gifts. And Cryptic throwing together a quick mission for the Free Odyssey / Bortas which took us to Mars Orbit / Gandala Orbit and giving the U.S.S. Odyssey / I.K.S. Bortas her shakedown cruise.
They said they wanted it as a Featured Event, which is a 5-mission story arc. So if they don't do it, it would somewhat be a disappointment.