Just had a thought..
Since Kinkaku and Ginkaku we're both sealed and used for their chakra in the Gedo Mazo, does that mean Edo's can be harvested for e.g eyes, chakra, etc?
Because the Edo Tensei has stopped and the chakra they had still resides inside the Gedo, so maybe Itachi could be harvested for his eyes? Or Nagato for his?
Just a thought.. You know..