Hello, dear client
We are very happy to participate in your contest.
First of all we tried to keep your requirements:
• we keep the load-bearing walls untouched, we use the existing openings in them
• all doors are all swing
• the kitchen front-linear 300 cm.
• bathrooms are connected to the existing pipes in waste columns, only the kitchenette of APP1 needs to reach a pipe
• All main rooms have natural lighting, the room on the north in APP2 lacks light so we propose to extend the height of its window if possible
• We tried not to move the places of heating radiators

We made 3 alternatives of organization of the space. Demolishing plans are also attached for you, also 3D perspective view of V1.
If you have any questions or changes, you can contact me
I hope you enjoy our design.:)