Gothamist today did a run-down of various mysterious storefronts on Van Brunt Street, and what the work being done on them may portend.
I believe I can shed some light on one of the mystery addresses, the plywooded-up corner spot at the southeast corner of Dikeman. This, I hear tell, is going to be a combination eatery/cocktail joint going by the name of Fort Defiance (a nod to Red Hook's military past). The cocktails will be haute, along the lines of those found at Clover Club and the like.
UPDATE: I am informed by a reader that Gowanus Lounge actually reported this news back in Jan. 28 (although that item identified the cross street as Van Dyke, not Dikeman). Apologies. Had no idea. Anyway, the owner, I believe is a veteran of Manhattan's swank Pegu Club.