The marriage between Will and Elizabeth would be very well known, because Elizabeth is so wealthy, plus I'm sure there were rumors buzzing everywhere about the governor's daughter marrying a blacksmith...someone well below her station.
The fact that Beckett knew about the wedding would not have been a huge shock.
As far as Norrington being in league with Beckett, I don't believe that for a moment. On Wordplayer, Ted said that Norrington was utterly devastated by Elizabeth's rejection of his suit, and by the fact that she used not only him but his men without thought, all to save Will.
Remember, Norrington was not the only victim of Elizabeth's love for Will...every death on the Dauntless during the first movie is technically blood on Elizabeth's hands because she not only manipulated Norrington, but also neglected to let James know that the pirates were undead.
Of course, Jack didn't let on that as well, so he is also partially to blame for all those deaths....
At any rate, James became obsessed with hunting down Jack, and he tried to sail through the hurricane...the loss of his ship and more importantly, his men, pushed Norrington over the edge.
Ted also said that he felt that James resigned on his own, instead of getting kicked out of the Navy.
The scene at the end, James' arm was being held by an EITC soldier. If you watch he jerks his arm away and mockingly bows at the other guy as he walks off.
There was supposed to be a scene where Mercer offers Norrington something in return for the compass/chest/heart in Tortuga, but it was cut from the film.
So I don't th think Norrington is working with Beckett...I think in the third film he will turn against Beckett and do something to redeem himself.
There's lots of rumors flying around about that too...I almost think that he would be the one to take DJ's place...to have Will do it just seems too...I don't know. Easy, I think.
Norrington's story actually mirrors DJ's much more than Will's does.