so what i get from this small juubi minion is it cant be sensed even by naruto sm .
its more perfect than white zetsu clones is stealth and hiding their chakra signature
then there was the duo of cho cho and sarada which is perfect still shin was faster and much better evading them both and almost killing chouchou , only naruto was able to save them , thats afirst to see an uchiha so caring about team mate after the whole senseless sasuke era , so heres my guess .....
both shin and sarada are saskue son and daughter from karin , both got kidnapped since birth because of the guy in akatsuki cloak and only sarada was able to be spared , so sasuke return with sarada as asmall baby and give her to sakura to take care of her while he go back searching for his son , he see him again after a hard brain wash from the cloaked guy that he is itachis son and should kill the one who killed him which is his father.
on second thought the kid looks so much like madara in eyes so my guess is he isnt his son , but madaras son .
the third and last thought is he is itachis son but still most unlikely .