Don't forget, Egon is the guy who said “Print is dead”… of course, in this day and age he's also likely to say “Peter, have you been playing video games again?”
My final thought on the WTC issue: the scene described above would look pretty impressive, and I think if the comic's creative team did decide to include the towers, it would be handled sensitively and with respect - no parodies, no dragons flying through the towers, no ghosts destroying them, no blowing the top levels off by crossing the streams… I mean, that would be just tacky.
It's a big *if*, and I doubt they'd do it. But if they did, it would be essential to the story.