the biggest testament to obito's cosplaying ability actually isnt the fact that he managed to fool minato into thinking he's madara at 12/13 years old or kakashi or OHNOKI. (who has actually met him before). its the fact that he also convinced kurama ... like it might be that its just kishimoto "forgetting" that this would be a huge plot hole actually but im choosing to believe that its just bc obito cosplays him so well ... kurama is intimately familiar with him. can sense his chakra. immediately recognizes it when madara tries summoning him after just having been resurrected. recognizes the smell of his blood, too, when madara later tries summoning him another time. but he still doesnt warn naruto before .. he knows that naruto and everyone thinks of the masked man as madara and it would be a vital piece of info to share w him that its not. but he still doesnt. at one point, when naruto and kurama start talking to each other more, he does also refer to him as "madara". im just assuming here that its NOT a huge plothole lol but just obito being INSANE at cosplaying. and fooling even an ancient demonic natural force w a personal history and vendetta against the guy into thinking he's him