In 2 Kings 24:18 and 23:31, it is stated that the mother of Jehoahaz and Zedekiah was Hamutal, daughter of Jeremiah. Is this Jeremiah the prophet, making Jeremiah the father-in-law of Josiah and the grandfather of Jehoahaz and Zedekiah? And are Shallum (Jeremiah 22:11&12) and Jehoahaz one and the same? --Ken Litle
Your questions are about men of the 6th century BC. The answer: different Jeremiah! Many names are repeated in the Bible, and sometimes we need to be careful in making identifications. But yes, Shallum was also Jehoahaz. A number of kings and others had more than one name.