Dear Client,
Key proposal for this modification is:
1. Maximize the usage of the space.
2. Well arrangement living room, spacious master bedroom.
3. Minimize the demolition.


Follow these points, I propose:
Level 2: A common area (living room, dining and kitchen) has balcony, a powder and shoe cabinet at the foyer.
A master bedroom with walk-in closet and ensuite bathroom will be great for you.
A stairs down to level 1 with minimum cut the floor and keeps the space for living room, and connects downstairs bedroom.
Under stair case is cabinet for more closets and storage.
Level 1: The bedroom is big enough with its own toilet and also has balcony.
The Studio has its own toilet, and can divide to a small living, kitchenette and sleeping area.

To me, the location of the stairs at the bottom left will be better, since we have more space there, and it connects the downstairs bedroom into living room - a common area. The stairs has 17 steps, according to the height you provided about 3.15m (2.9m clearance and 0.25m slap thickness) each step is about 185mm high.

Thank you for the opportunity to work on this project.
Best!