what the author motive was
contradicts
Analyzing an author's choice of language, tone, and style can help infer their beliefs or perspectives. Additionally, examining the context in which the work was written can provide insights into the author's mindset. Comparing the author's work with other works or personal statements can also aid in understanding their beliefs or perspectives.
It is okay to write a book on something that is copyrighted, but you cannot publish your work unless you get permission from the author.
If doing a sources cited page, there is no need to identify that the author is deceased. You will want to write your bibliography as you normally would, including the name of the author, the work of the author, the date of the published work, and the date it was accessed.
A free author can write whatever he chooses. But a commissioned author has to write what he is commissioned for.
An author would think plagiarism is a grave offense because that is who they are. They write, they are known for that, the things they write make them who they are. If you take the work they produce as your own, it makes them incomplete.
No. If you take all the words from a story and write a poem from it, that is plagiarism. However, you should be careful when copying other author's work.
You may only write about another author's character if they give you legal permission to do so. Unless the original author is dead, you are probably not going to be hired to write a sequel to their work. You may write fanfiction, which is writing that cannot be sold, but is just "passed around" on the internet for enjoyment. So long as you do not try to get any sort of "payment" or recognition, the author will probably ignore your writing.
You're not going to find an author who will write a story for free -- we like to get paid for all our hard work. Here are some good links to help you learn how to write your own stories!
An author works whatever hours they wish. Some work four hours a day, others as much as 12. It really depends on how they work best, some like to write in the mornings, other late at night.
Saint-Exupéry wrote mostly novels.
An author is unlikely to write something with which he or she fundamentally disagrees.