Ezra and Nehemiah

The most wild conjecture
I can make to validate modern academia's theory about the Bible true
Is that Isaiah II convinced a bunch of 
Completely ignorant people that they were Jews
And then somehow got a license 
From the king to go to a remote
Desert in the middle of the earth.
So, if hypothetically the Bible were written in Persia,
And just thrown together with a bunch of 
Random historical texts, some impromptu prophecy
And some Sumerian Mythology thrown on top of that;

Where was Ezra and Nehemiah written?
Obviously, it had to be written by the Jews
After the fact. And, it catalogs the rebuilding
Of actual walls, the rebuilding of an actual temple;--
And then there's protectorate kingdoms of Persia attacking them
Constantly, who verbatim know these people are Jews.
At the very least, it would be suspect---
That this invented race in that invented moment
Would come to find the ruins of a city
Which was conquered seventy years earlier.
And then, the surrounding people
Knew this invented race,
And decided to harangue it.

There's a lot of assumptions.

Most likely, the Jews had an actual historical
Scripture, an actual lineage of kings from two separate kingdoms,
With a Law infused with Oral Traditions written down by Moses---
Whether they were Sumerian, I'm suspect to think
That the events were shared by many cultures,
As most things which are true are---
So, these stories were preserved by Moses
And handed down to the Jews in accordance with their
Torah, and the Bible really were written over the succession
Of 1300 year prior. I'm even apt to believe
The verse about Cyrus were in the original Isaiah text;
As, certainly, Jesus is in Isaiah too, in the most literal terms
In the 53rd chapter.
It's not hard for me to believe, at all.
What's harder to believe,
Is the series of strange, misshapen events
That don't conform at all to what we know about basic human psychology.