Was Minas Ithil ever retaken? If yes? By Who?
Minas Ithil is eventually rebuilt, but not until many years after the War of the Ring.
EDIT: As best as I can determine, Tolkien did not provide details on when it was rebuilt, though the kingdom of Gondor likely reclaimed it after the conclusion of the War of the Ring.
It is important to note that Aragorn ordered that the original city be razed to the ground because it was tainted too much by the Witch King and his forces. I would assume Minas Ithil would not be rebuilt until the taint was gone. That may have taken centuries, so maybe it happened even after the reign of Eldarion.