"the district claims the adaptation of the diary was never approved"

Ah yes. Nothing says "Freedom!" like books having to be on an Approved List. That doesn't say "Prior Restraint" that says "Freedom!"

"The school district returned the book to library shelves"

It's on the shelves... But you're not allowed to look at it or present it. In fact, that's a termination offense.

"Not required by the school, but by my mother."

When we were kinds our mothers made us visit the old lady up the street with a Nazi serial number tattooed on her forearm.

"This was a "GRAPHIC NOVEL" reinterpretation."

^
"The school district returned the book to library shelves"

#13 is there not a difference to it being on the approved list, and required reading vs just being available and on the shelf?

^
Your Papers, Please.
You don't have Papers, authorizing you to teach from a book, that is on the shelf in the library?
You lose your job.