When i first saw the plan of the villa I immediately saw two rectangles (one on the left and another on the right) and in between a larger one which naturally turns to be the private rectangles on the side and the reception area directly in front of the main entrance. I did larger openings on Living area as an invitation to your guests to go towards the light and the garden in front will be the Cherry on top.
I also suggest to remove part of the first floor slab in order to give more life to the living area but also to emphasize of the reading area with chimney and "chaise longue" and it's superb double height bookshelves. The void could be recovered later on if needed as we left some beams to facilitate the job, in case extra space is a must but meanwhile you just enjoy the double height.
The extra large reception space is an open space as required but with small partitions (not in full height) to give a little privacy to each area (living, reading, dining, stairs).
The general ambiance is zen and cozy with medium grey concrete finish flooring, white walls, light grey ceiling paint, wood furniture that add warmth to the space. Colors should be brought with the accessories (paintings, covers on chairs and sofas, books, flower pots etc...
Even with a small extra budget that maybe needed but i guess it worth it to do big works once and for all as it is a lifetime project.
Hope you like it.
Cheers