...Naruto's original plan had been to deal with his mother Kushina's situation immediately after settling Gaara down. After all, the power of his "Menma" form had a limited duration and had already dissipated, while his own Nine Mask Svāhā had yet to be summoned again.
However, he had long since left Flying Thunder God marks on Kushina and Mito's Edo Tensei bodies, so he was not worried about being unable to find them. Moreover, the Sealing Jutsu placed on them was both a restraint and, to some extent, a form of protection. At the very least, it ensured they would neither cause destruction nor be harmed while out of control.
How long had it been? Old man Third and Jiraiya had already found and sealed them?
On second thought, Naruto found it perfectly reasonable. After all, the battlefield traces left behind by "Menma" fighting the previous two Kurama Jinchuriki had been on the level of a missile bombardment. It would have been difficult for them not to draw attention.
"Then..." Naruto drew a deep breath, and the form of address slipped naturally from his lips. "...Mom, where is she being kept now?"
When Third heard that address, his eyes visibly wavered. He fell silent for a moment before slowly saying, "Kushina... Lady Mito, as well as the First and Second Hokage, are currently being held in a special room within Konoha's Anbu base, the one used to store classified scrolls."
"For now, unless we can persuade Orochimaru to willingly release the technique... we have not found any other safe way to undo this forbidden jutsu."
...No, Naruto actually knew one method—[Edo Tensei Release].
So long as they knew the hand seals, the souls of the dead summoned back could, through their own will, actively dissolve their contract with the living