Hold on ... didn't Dukhat come later in B5? I thought he was retconned into B5 early history in the movie In The Beginning.
Not at all. He was mentioned as early as 'Soul Hunter', episode 102, and again in several other episodes (A Voice in the Wilderness, A Late Delivery from Avalon, Severed Dreams, Babylon Squared and Atonement).
True, though because of the 1 year delay in the production for B5 Season 1, "Soul Hunter" wasn't produced until well after the character Dukat appeared in DS9's premiere.