In the room of Josiah his father - Not “in the room of Jehoahaz his brother;” the phrase is intended to mark the fact, that Neco did not acknowedge that Jehoahaz had ever been king.
Turned his name to Jehoiakim - Compare 2 Kings 23:30 and 2 Kings 24:17. It seems likely, from their purely Jewish character, that the new names of the Jewish kings, though formally imposed by the suzerain, were selected by the individuals themselves. The change now made consisted merely in the substitution of יהוה yehovâh for אל 'êl (“God, Yahweh, will set up”). Both names alike refer to the promise which God made to David 2 Samuel 7:12 and imply a hope that, notwithstanding the threats of the prophets, the seed of David would still be allowed to remain upon the throne.