Diving a room ideas. How can I somehow add a door?

You need to be careful that you don't create an inner room. That is to say you are aware of a fire happening in the living room before you become trapped in the bedroom area. If you have a window to get out of this may not be a problem. Have extra smoke detectors as a precaution. That said, you are almost certainly going to need to get/make your closets in sections to get them into the room. If you arrange them to have a gap between you can fit a regular or bi-fold door with a frame.

Lots of ideas here. http://shameonwinndixie.com/free-standing-wall-div...

Notice how they get around the inner room issue by not going right up to the ceiling to allow some ventilation. I would think about a lightweight pocket door by having a couple of book shelves back to back as part of the closet and connect a head rail from them to the next full depth closet. The door slides away neatly into the gap. Everything can be freestanding but you might need some bracing. see link for ideas.

http://www.drwallny.net/bookcase-wall

https://bel-jackets.com/pqvxns33917/

You won't get sound-privacy without building a wall and putting in a properly-framed door.

We did this to our living room when my daughter moved in temporarily. We have a LOT of books and 6'tall bookshelves, so we just moved them. For a door, we left a gap, screwed a dowel to the bookshelves on each side, and safety-pinned a curtain on the dowel.

You have to careful that no one stumbles into the bookshelving and knocks it over.

One COULD buy a piece of masonite or chipboard and use hinges to attach it one side.

Hang a drape.