Form of the building came into existence with the help of function you asked for and my comments of the site and the requirements. For example although you want a rectangular form on east-west axis, I propose a rectangular block with sloped roof on L shape mass. I would like to explain the orientation of a building side by side:

EAST: The entrance side. There is an entrance porch which can be used also as a dinning terrace during hot summer. It is easy to reach this porch from kitchen. Moreover there are two studio rooms in ground level which has morning light and Ionian sea view.
In the first level there is one private balcony for each bedroom which has also wonderful sea view.

WEST: Unlike you, I would like to have a long facade in basement level for two reasons. First of all if you want to have a bright basement while using potential of natural topography, this facade is the only way to reach sunlight.Furthermore I would like to see Tyrrhenian Sea as much as possible. With the help of this perspective, there would be outdoor space activities in the basement level insulated from the life all around the land.

SOUTH: South is so important not only for interior spaces to gain more energy but also for PV panels to use sunlight. Panels are positioned to the south. So slope of the roof should be toward this side.
It is a good idea to built winter garden in here to have more light. Additionally it is needed to have direct relation among living room, outside and winter garden.

NORTH: Building should have less opening in north. Outside in basement level there is a car parking area for people living in this house and they can use workshop door to enter the building. There is another car parking area in ground level for guests. It is so close to main entrance.
In the first floor level there is a terrace for technical equipment. For example PV panels or air condition system would need such space.