I would suggest you take out the cabinet that is to the right of the stove and use it elsewhere in the house -- perhaps in the bathroom or dining room with a hutch above it. Then, I would suggest you have someone install a lazy susan cabinet in the corner between the sink counter and the stove, meaning you would move the stove down a bit and have a small cabinet/counter top to the right of the stove. I would suggest you have the cabinets refinished in white and then paint the walls a pastel you like. If you would prefer white walls, then add white-painted crown molding and paint the ceiling a light neutral blue, such as Sherwin Williams Niagara Falls Blue. Then, I would suggest you choose a favorite accent color and use this sparingly in accessories like towels, pot holders, small vases or floral arrangements, and a valence above the triple windows. For a genuine 1940s look, you might have white ceramic square tiles with a rectangular red border installed as a back splash behind and above the stove. If you are replacing counter tops, I would suggest a light color such as white with a beige or light grey vein or striation for some sort of pattern. You might be able to find the same color and design in floor tile OR opt for a wood floor as another poster suggested.

And the seating areas are different, don't try to make it look like one area. I would put minimal ( if any) teal around the black sofa. Do your dining room. Then give you living room the same respect, it is it's own space

I like your plan but I don't think a pattern on the bed wall is a good idea. The carpet already has a lot of pattern so I'd keep that wall a solid, dark color, from the rug. Add some sparkle like mercury lamps for the bedside tables for interest.

A small sink would fit in the second floor plan w/c. its 2.8mx 1.4m so definitely enough room. If we use the last floor plan with separate w/c then it opens up the bathroom to be 2.7mx 3.2m which for New Zealand standards is a big bathroom for a shower, bath and vanity. I'm still trying to decide if the space for the dining and kitchen areas are big enough?