Dear Client, here is my design proposal to you.
For the living room, I tried to use current shelves to make some kind of shelving wall system by adding some new elements and creating a new geometric form.Dimensions of new ones are made by dimensions of shelves you currently have. At the end of this wall unit, there is one single shelf/working desk "deskbox" by arco which by single extension becomes nice work space (see pictures). For the rest of furniture, I have used one two modern armchairs, coffee and one side table and , one more open shelving unit by the windows and sideboard. I think that living rooms should mostly stay simple and clean , keeping its simplicity and aesthetic, because its already a dining place too, without too many storage for which I found solution in hallway.
Dining area contains extensible table up to 300cm so it completely meet your needs.Colors are mainly bright, with some accents like turquoise and yellow.

For the kids room, I wanted to make playful but also soft and calm place for growing. There is a bunk bed, angular wardrobe by Nidi ( HIinged door wardrobe system-Angolo spogliatoio “M3”) with woody hooks,. There is also desk, toy box, and shelving systems. My suggestion for kids room is to install climbing holds by the bed and secure floor with matts, so your kids could possibly climb to bed by ladders but also practicing motoric skills and climbing by holds, kids find it extremely interesting. To provide more space I'd also add to bunk bed two storage boxes .

For hallway, I'd go with two " JESSE - Plana" sliding wardrobes in front of windows, dimensions H262-W160-D60cm. i think it wouldn't affect too much on walking trough hallway but it would be a huge help to storage. Up to the ceiling I have idea of making gypsum construction, which wouldn't be very expensive but could be a great space to make a small hallway library . Construction could be covered with wood from the inside.
Art from the living room you can find on zgallerie.com
Rugs in living room are Boconcept - Adana, Wayfair- Arnott hand tufted rug.
I hope you'll like this project.
If have any doubts, feel free to contact me.
Best regards,
Tijana Zdravkov