My solution for your house is an open plan configuration with livingrom, kitchen, dining and bathroom at the groundfloor and a simple distribution of 2 bedrooms and 2 bathrooms for the first floor
The floors are connected with a simple modern stair towards the East, near the windows.
The house is oriented so that the largest windows are towards South and East.
I have chosen to put the pool on the East side so that the terrace towards the pool will face East and not North which would be too cold and dark. If you consider so, the pool can be extended almost 1 m to the East and much more to the North to make it longer.
There is the possible to close the terrace with other large windows or glass walls as indicated with red line on the floorplan.
There is also the possibility to have two entrances eaither from the North or from the South as indicated with red arrows.
The total area is around 128 m2 which is very close to your requirement.
For the old house, i suggest that you change the arches from the portic and make them squared, which is much modern, clean and even allows more light.
The new house should have the groundfloor portic and walls the same type of stone cover just as the old house (as indicated in the facades drawing.
The other materials are timber cladding and white plaster