My proposal for each apartment:
1. Big living room + dining and kitchen.
2. 3 bedrooms (1 double bedroom with area~14sqm, 1 master bedroom with walk in closet and ensuite bathroom, these two bedrooms can have bed size of 1.6x2; third bedroom can have bed size of 1.4x2)
3. 3 toilets, one is in the master bedroom, one is a shared toilet for 2 bedrooms outside and a powder room for common area. Toilet layout is 4-piece bathroom (sink, toilet, bidet, shower), this can be changed to 3-piece layout depend on demand.
4. a laundry and storage area.
I have proposed option 1 and option 2 for comparison.
Option 1: kitchen at the same area with living room and dining (this kitchen can be closed/ or partially closed if you need a hidden kitchen, to me an open kitchen will make the space bigger)
Option 2: kitchen is at the side and this is a hidden kitchen. The advantage of this option is the kitchen has window. The disadvantage is the common area is a bit smaller, we will lose some space for shared foyer for 2 apartments before entering each house.
I would propose OPTION 1 for this modification.
I also attach the detail for the partition that come in the middle of the window, turns the window to shared window for two room. Since we don't have enough windows for each bedroom, this is a must to do in order to achieve each house has 3 bedrooms.