I went downtown today on account of not having to work, and it is really starting to look like what they're filming takes place during and in the aftermath of Man of Steel Zod fight. The ATT building now says Wayne Finance and I saw Amy Adams down there as well.
It reads like the writer has some things mixed up, that or I just know too much about comics. But Kryptonite coming from the world engine or its terra fomed area makes a ton of sense and is a nice callback to superman returns.
However Doomsday's Origins is that he's an alien hell spawn that keeps coming back and adapting. By using the corpse of Zodd it would be more apt that his will be the Origin of Bizzaro or maybe even superdoom.