Those are artificial "structures", in my opinion. There are not 5 prophets, unless you group some of them as "one" prophet, like Josephus tried to do in his numbering. It is not uncommon for men to try to make more meaning out of something by artificially categorizing writings. There are not 5 history books, and there are not five of anything in the New Testament. The Bible is not arranged in a "Pentateuch" fashion.
God inspired the sacred authors to write what HE wanted written, but that doesn't mean that we have to try so hard to make the bible fit some sort of pattern with a higher meaning. What is inspired are the individual writings, not the Bible as a whole so that we can take the various books and make such "holy arrangements". It is the Church that devised the Bible into its present format. Originally, the Old Testament was written independently on many scrolls, not in a codex or a book.
I share your caution here, but think about it. If scripture is really the word of God, shouldn't we expect it to be awesome beyond belief!
It is. I find, though, that such studies are not necessarily the intent of the Lord. I believe that the Bible was written to instruct us how to live, as 2 Timothy 3 states. All that other stuff, while interesting, is not very conclusive or meaningful, in my opinion. If people pore long another over Shakespeare, they will find similar patterns. I believe someone did a study on just that in an answer to the "Bible Code" books, that series that claimed to be able to predict the future by looking at the verse of the Hebrew Scriptures. Another person answered that with secular writings and showed the same thing. Thus, I do not put much stock in what you are saying.
Regards