Upholstery and egg crate type foams will not be rigid, and may not be flame retardant. EPS and XPS construction insulation foam are lighter weight, more rigid, and could be covered with batting and fabric. They come in 4'x8' sheets, but can be cut with a utility knife into smaller sizes. They are available from a big box home improvement store like HD or Lowes. Not sure if they are flame retardant. Depending on how large a piece you are mounting, I would think they may be light enough in weight that they could be mounted to the wall with 3M removeable hangers of some sort.

So sorry.....I see the dimensions on your floor plan now....oops. It was middle of night here. You have a great place with lots of options. I will try to find a picture for you, but here is what I would try. TV on left wall. Put it on a console table 20" to 30" high, or wall mounted with a wall mounted console below. TV should not be too high or too low for viewing pleasure. The main walkway to the balcony will be on left side in front of TV. To see how the arrangement feels, Try your sofa on the right wall facing the TV. Then put one of the chairs in front of the sofa with its back to the glass and the other opposite of it with the back to your entry. If you feel this arrangement is too far from the TV, a sofa table can be used behind the sofa to move the whole seating arrangement forward. Then if this feels good, you can add a rug. The rug should be at least big enough that the front feet of the furniture can rest on it. You will then need tables on the sides of your sofa. You have the choice of a coffee table or what is called "cocktail ottoman" which you can put a tray for drinks and food on, but still put your feet up. That is always nice when watching TV. If you like this arrangement and go to buy new furniture pieces,get the chairs on each side of the sofa that swivel so the person can watch TV easily. You need to think a lot about what colors you will use in this houses if any rooms are done, take some cues there. It's a big decision that will influence every purchase. Find a 3 color combo that appeals to you. Again look on Houzz at the living room pictures. Post some here that you like.

To decorate any room in the house furniture is the most important element. choose the furniture according to your style and personality. there are many types o bed are available for the bedroom like king bed, queen bed, canopy bed, bed with headboard and foot board, loft bed, storage bed etc. select bed according the theme of the bedroom and need. for living room or hall you have many option. you can arrange sectional, sofa, loveseat, recliner, seating bench etc. see decoration idea http://www.theclassyhome.com/comersus_listItems.asp?idCategory=348&Furniture=Living+Room+Sets

Is the indent in the wall where you have the TV now, supposed to be for a TV or is it to be a closed up closet?? You could switch the room with living area where you walk in but then you cannot wall mount the TV due to windows. Plus you might like eating near windows for more lighting drama. Also , now seeing your hall , I think turning the dining table 90 degrees from how I placed it, would fit better in your space. You could consider an area rug under the table as well , which would help to define the space when you enter. Also keeping a runner and a vase with either fresh ( or nice fake) flowers on the table, will make it flow better with the living room area furniture.