The answers to my questions are provided in the relevant scholarly works, such as Bible Commentaries, and surveys, at least.
Without going into extensive details, the broad answer is that Kings was drawn up into its current form (based on earlier annals) in the context of the neo-Babylonian Exile (6th century BCE). Today's scholars use the term "Deuteronomic History", seeing a unity in Deuteronomy, Judges, Joshua, Samuel and Kings. The book of Kings thus placed a certain bias on the record of the events from the view of the time - nothing wrong with that, but it needs to be noted.
Chronicles, however, was written some 200 years later, and subtle differences show that the author(s) felt the need to "correct" the record to make it accord with their understandings. One example is the difference in the way that Kings and Chronicles records the experiences of King Manasseh of Judah.
Recognising the human narrative that lies beneath the record they left (repeatedly edited, of course), helps to provide the best understanding, rather than thinking these writers and editors (redactors) had us in mind.
Doug
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The setting of the book(s) of Chronicles is the postexilic community of Judea. Nevertheless, the specific time of the writing of Chronicles remains open to debate. Proposals range from the Persian time frame (400s BC) to the Greek/Hellenistic time frame (300s-200s BC) to the Maccabean/Hasmonean time frame (100s BC). … Observations indicate a likely range of 430-340 BC for the writing of Chronicles, with some preference for the earlier side of this range (ca. 430-400 BC). -- The Expositor’s Bible Commentary: 1 Chronicles-Job, pages 25-26, Tremper Longman III & David E, Garland, General Editors, Zondervan, 2010.
The Chronicler is not a historian in the strict western sense. To him Israel’s history was pregnant with spiritual and moral lessons, which he brought to birth through a kind of historical midwifery. He is not concerned so much with the bare facts of Israel’s history as with their meaning. If all valid historical writing is interpretative, the Chronicler’s is highly interpretative. Above all, it is paradigmatic history. As a paradigm tells us how to frame the various tenses of a verb, Chronicles tells its readers how and how not to live, by presenting both positive and negative role models. – Old Testament Survey: The Message, Form, and Background of the Old Testament, page 543, William Sanford Lasor, David Allan Hubbard, Frederic William Bush William Eerdmans, 1982, 1986