i think i figured out something about kabuto. in the manga in ch267 on pg 4 chiyo says sasori aided orochimaru in killing the yondaime kazekage(garra's father) and sasori says that wasnt him it was his subordinate. i think he was most likely talking about kabuto

EDIT: in ch275 p11 he tells sakura to head to grass village to meet his spy in the sound village, one of orochimaru's subordinates. more stuff possible aluding to kabuto