Hi Jeffro
I do not use Josephus as the basis for my conclusion. It just happens to say something similar.
I said you use Josephus to support your position. Josephus takes his information from 1 Esdras, assumes that it is in chronological order and that 'Artaxerxes' was Cambyses.
It's also interesting that he didn't think to associate the 'Artaxerxes' letter with the "Magi" (Bardiya) who "attained the government of the Persians for a year" (Ant. 11.3.1).
The author of Ezra/1 Esdras (whichever was first) could have used the wrong throne name (which doesn't identify a specific king) but known which individual and period they referred to.
'Could have' reflects conjecture, of course. The author or later redactor 'could have' (and IMO more likely) got the right throne name(s) and mentioned it (them) out of sequence as part of the 'opposition' theme. 1 Esdras, as you admitted above, "associates events under Darius with events under Cyrus for literary purposes, however the rest of the book is in chronological order." If 1 Esdras can deviate from chronological order there, then it and Ezra conceivably 'could have,' deviated from chronological order with the first mentioned 'Artaxerxes.'
This does not require that the king was broadly known as the other name. The author of E[z/sdr]a[/s] could simply have confused the names, just like Josephus does.
Or he 'could simply have' NOT confused the names and placed later 'opposition' events in with the 'opposition' summary.
Or he could have jumbled events from kings from both periods. Or he could have made the whole thing up about the letters.
Indeed he 'could have' made the whole thing up. In that case, this textual passage is useless for chronological/historical purposes and it is pointless insisting on a timeline (one way or another) for Ezra 4:6-23.
(How did the author of E[z/sdr]a[/s] get the letters?
Unknown. How did he get a copy of the letters between Tattenai and Darius or know that they found the memo about Cyrus' order in Ecbatana?
Are we going with the 'inspired' [aka 'magic', aka superstitious nonsense] theory?)
??? I hope we are going with an approach that tries to harmonize ancient Jewish accounts of history with other historical sources. What has the subject of 'inspiration' to do with anything?
Anyway, I think we're at a stalemate.