There are tons of papers available that would go with your midcentury home. Many people tire of a paper quicker than they are ready to redecorate and they can also look dated in a couple of years. Metallic papers were big im midcentury...perhaps a metallic silver paper? Are you also considering paint? You can get it in so many textures and a blue wall to match the blue in your loveseat would be lovely with some midcentury art and sculpture, or photographs on it. A mirrored wall with or without art or sculpture would also work with midcentury. These treatments are easier to adapt should you wish to change the look slightly from time to time. I would suggest replacing your stairrail with chrome or acrylic if that is in the budget...see how well the loveseat frame looks with the fabric? I hope you will post the "after" photos for us to see. Above all, enjoy the process!

Oh, okay, may need to clarify some more. If you get a new 2 seater in place of the 2 white chairs, fine, but no blue chair at all next to the 'new' 2 seater. Won't be right with a blue chair too. So what ones are you planning to recover?. If getting rid of part of it, not understanding. 2 different styles placed next to each other won't look right. I wouldn't like old blue fabrics next to new fabrics or next to 2 different styles of furniture. New 2 seater and old blue chair next to each other, not good :)

How about flanking the window will billy bookcases? Paint over the green wall an off white and just pick a color you love for the bed wall. A stylish chair for your desk and maybe "industrial" looking bedside lamps will "man" it up. :) Plus, get a cooler looking desk chair...in a color that you paint the bed wall.

Add a fabric wall hanging – looks like there is space on the wall behind the Chesterfield loveseat? A woven shawl or table runner from your travels overseas (if you've bought anything) on a dowel would complement your Tintin in Tibet art, and not add clutter to the space. And an ottoman that doubles as a storage box or small coffee table (put a tray over it as a stable base for your coffee) would be nice to put your feet up on as well as add to the bohemian look.