This home is very interesting for analysis, but not only from the architectural aspect.
First house room is divided on tree zones: entrance, living and dinning zone but they are visually connected with the path of suspended ceiling, materials and transparent furniture.
Living zone on the right side is little bigger than you proposed. The position of sofa in the angle can give you a sense of narrowness and it will be better in the center. It is also good to have solid backup like wall (not windows) behind sofa where you usually sit because it can brings you a sense of security in home. Monolit peace with TV is strong enough to define that zone for enjoying and repose. Still glass shelves are transparent and they allow impression of space unity. My proposal is to cover bricks behind the fireplace with light stone and to replace the existing furnace with modern one (during the time) because that will harmonize hole space in one modern way. Beside the dinning table is aquarium (if you have a possibility to have it, live water can bring you great opportunities in life, specially because water support eastern energy).
I hope I can help you with these advices. Best regards.