There's no 100% guarantee of course, but if they stick to their usual way, in all likelihood all of both the pre-order and edition exclusive DLCs will be available roughly 3-5 months later if I had to guess on the timing of the Brotherhood and Revelations DLCs.
It most likely will. They'd be stupid not to do it as they can charge for it, so those who missed out can simply pay for it.
However, for ACB there was a rare pre-order armor set that got released with a DLC batch, so while we may not get the outfit/weapons as a stand alone, they may include them both in one of the unannounced DLCs.
Probably so, like was previously said, they can release it on PSN later and charge money for it.
So it would be like someone who decided to wait til 2013 to get the game and say something like "I wonder what kind of DLC they got for this game." (<----- Casual Gamer) and they go online and see what we know as the pre order bonuses and regular DLC and pay like 10 to 20 bucks extra for a pack.
So it goes like
-Put pre order exclusive DLC on PSN -Casual or Veteran/Hardcore fan buys it -???? -Profit
OFFICIAL GRAND MASTER ASSASSIN OF NORTH AMERICA/UNITED STATES AND ALL THE ASSASSINS CREED BOARDS