CONCEPT:
In this design, all of the main room (bedroom, bathroom, living, and dining) has direct access to natural lighting & ventilation, which is a very important part of living quality. Every needs area fits into the main apartment, so the cave area can be turned into a storage/wine cellar. There is no alternation to the fixed elements of design (opening, windows, bearing walls, and utility shaft) and we tried to change the layout as little as possible, while still completing all the needed briefs. In doing so, we tried to minimize your budget on renovating, while having your dream apartments. Hope you like the design. Thank you!

PS: for the separation between dining area and living area, we propose to add a wall opening to differentiate the two spaces. If you still think it is not enough, you can add a partition behind the sofa (see on the layout). But we recommend to not use the partition so it will feel more spacious.