Re: DS9, Worf and Continuity.
Nope. They do acknowledge (often by Worf saying so) that he was never a very good father, though he did give it a try at least a couple times. Also, when Alexander went back to Earth (presumably following "Generations" and the loss of his home, but really at any point from "Birthright" onwards), it was arguably so that Worf can so his post-Troi solo soul searching or whatever (no families on Boreth?) and there's no reason to believe that the two would not be reunited at some point following that.
Then Worf got called to DS9 and the Klingon tensions got bad, Worf got offered a promotion, and it wouldn't be a very safe place for Alexander and his heritage to be caught in the middle. Then Klingon stuff got better but the Dominion War started almost immediately after. Was Worf in the wrong place in the wrong time? Was he really running away or was it equally the circumstances that kept him from bringing Alexander to DS9?
I think I can agree with most of your points. It would make sense that Alexander go to Earth after the Enterprise was destroyed in Generations and while Worf was being all emo on Boreth he would have stayed with his grandparents. BUT Worf still gets the worst father ever award for not even knowing his kid had run away from home. I guess he was too busy getting it on with Dax to call home periodically