Re: And, missing the point as much as humanly possible--
I've never read that book.
The only actual examples of first-person omniscient I know of are A Dead Man in Deptford and Kurt Vonnegut's Breakfast of Champions. In BoC, Vonnegut is both the omniscient narrator of the story--he tells it from the point of view of the Author, referring to himself in the first person--and also a character. In A Dead Man In Deptford, the narrator is ostensibly a player-boy who was Marlowe's occasional lover. But who knows of and speaks authoritatively of things he could never have seen, and the states of mind of various other characters, using an omniscient mode where he can dip in and out of other characters' heads, or draw back for an objective voice. (There's a twist at the end of the book, as well, regarding the POV.)