Well, Dukat is posessed by Kosst Amojan, and Amojan is re-imprisioned in the Fire Caves. The Sisko is not killed, he goes to have non-linear montage sequences with the wormhole aliens. So what about Dukat? My guess is his body is destroyed.
I am guessing that Pah Wraiths have no more use for Dukat so his body burns up just like Kai Winn.
But the aliens in the wormhole do have more uses for the Sisko, if only to have more understanding of this concept of linear time. That's why he was the Emissary. He isn't an emissary from the prophets to Bajor, he is the emissary from linear-minded people to a race of non-linear-minded aliens.
I think that people will know that the Reckoning did happen, but I don't know if they will realize Dukat's role in it. Certainly the Cardassians are busy with far more difficult matters. Their homeworld is in shambles, and their population is decimated. The people who Garak saved, the dissidents who believe in democracy, will return to establish a New Cardassia that might someday equal the highly developed civilization Picard refers to in "Chain of Command".
Dukat is dead. Kosst Amojan, the Pah Wraith, endures but he is imprisoned. The book of Kosst Amojan is destroyed. Perhaps in a thousand years someone else will try to free the Pah Wraiths again. But not Dukat. He's dead, Jim.