As an aside, Erin and Abby have slightly different backstories in the Tor novelization. I don't believe that Paul or Katie had any input on that, as novelizations are treated more like adaptations, whereas we were lucky to get more of a hands-on treatment with the tie-in book. Nancy Holder's novelization is fantastic, though—definitely read it!
14. Was there any debate about holding onto Tobin or was it always going to be a new character - Kemp - who created the modern classification system from the start?
ANDREW SHAFFER: There was never any debate about it—Paul Feig didn't want to reuse any of the faux books from the original universe, so I had to create an entirely new set of reference guides along the lines of Tobin's. There were one or two mentions of fictional reference books or authors in the script that didn't end up in the final movie, but the ones in the book (Archibald Dutton, Vernon Heiss, and Maureen Kemp) were ones I created just for Ghosts from Our Past. I also designed faux covers for several of the books, which you can find at www.ghostsfromourpast.com
Interestingly the Tor novelization does mention the Spates Catalog, Tobin's Spirit Guide, and the Roylance Guide on page 36. Another of the interesting contrasts between the two.