Torah (the 5 books) is [considered] G-d dictated, holistic and include all the necessary knowledge. It is allowed to be passed in the written form.
The detailed interpretations were given orally and are to be passed in that way and forbidden to be written.
G-d notifies, that eventually and occasionally, He will appoint additional prophets, people should listen to.
I have difficulty understanding why #3 falls into category #1, as it isn't Moses' prophecy and is "extra Toranean". Besides, as per various Gemmoros (see B"B 15a) Na"ch wasn't written by the originators, but by much later generations.
If the Torah includes everything, why do we need additional books? And if they are extra-Toranean what permission is there to write them down?