I'm starting to think this at well, but wouldn't Sasuke have more of an emotional reaction if he learned he could bring back his parents in some way? Or perhaps learning the truth about them from Obito changed his opinion of them.CORRECTION :
Its "THEM".
the one who knows everything (according to Sasuke) are his parents.You must be registered for see images
But there is a possibility that Orochimaru will pull out Izuna too. Since he had Madara's dna, he might have Izuna's dna as well in his pocket.
Even Madara's dna was not in Uchiha district but still Oro found out (not from he Uchiha district), didn't he?
Either way IMO I think it'll be:
1) More than one person
2) Re-animated Uchiha