Dudu: some students get in early through QuestBridge, which partners with Princeton. Also, some of them might be athletes who have gotten 'likely letters,' but technically not acceptances yet.
Saugus: Princeton Econ is strong, and certainly one of the top few in the world. It's hard to say that it's #1 in the whole world though - let alone the country (Chicago, Harvard, Berkeley, for example, all have competitive programs as well). It's a fairly large department at the undergrad level, and I don't think they reject anyone, as long as you sign into econ the first time around. I've heard that it's hard to switch into econ junior year though, because of how big the department is.
Rooms in Whitman are really nice, as they're still very new. They're mostly singles and quads, all communal bathrooms (no bathrooms in the rooms). Sizes range from small-ish singles to huge five-room quads (but these are almost always taken by seniors, so don't worry about getting them

).