I agree that the ON is absolute, but doesn't tell all she knows. I think the ON's voice is JA's. Sometimes she simply holds back information from us, sometimes her wit or irony obscures the truth, at other times, she slips from the narrator's voice into the more subjective thoughts of Lizzy or another character. But she never tells us, as the narrator, something that turns out not to be true. There was recently a link on the Emma board to an old post by Laraine about JA's "free indirect style" which is very enlightening on this point. Unfortunately, I was unable to find it through a search!