mastermind story plot

Hey Gordan Korman I was wondering when you were writing masterminds more specifically the part when Eli finds out he is replicated from Tamara Dunleavy in Book 2 he thinks he is cloned from The crossword killer… Is him finding out who he was really cloned from your plan all along or is it something you thought of while you were writing it and why did you choose Thin Mints specifically for the Girl Scout Cookies that Tori sells is there any reason at all?