Dear Stefano
Thank you for sharing your amazing project. I also created a virtual tour of the living dining, kitchen and your master room to let you immerse in the area.
https://kuula.co/share/collection/7PkGp?fs=1&vr=0&sd=1&thumbs=1&chromeless=0&logo=1

I created 2 alternatives for the layout of your bathrooms. I recommend the one with a bathtub as you requested for a bathroom full of light that recalls the sea and the heat. In this design I created a spa like bathrooms with appropriate water resistant wallpaper and tile to make it feel natural and airy.
For the living room I created a layout to have some separation between the entrance and the living and dining area. In the entrance there’s an entry closet too. Part of dining seats are like built in benches to let you utilize the space functionally. In this format you can use it for a lot of guests.
For the kitchen I tried my best to create an interesting layout not being conventional. You have all the facilities that a kitchen needs and even more like wine fridge. You also have the island and the bar that you wish to have. I also designed the outdoor area and you can have the barbeque, outdoor dining and bar close to the kitchen for easier access.
For your master bedroom, I created a shop like closet that you asked for and by adding timbers as a dividing wall I placed a mirror for more functionality and some privacy when changing clothes.
For the other room I thought having a guest/study room would be more ideal. You can have a sofa bed to turn the area into a guest room and you also can use this room for home office and when you’re tired simply use the sofa for a short rest. You also have a huge closet here to be used for storage and clothes.
In your color palette I combined gray hues with earthy natural colors and for the design I added natural materials like wood stone and some steel to be close to your ideal modern style.
Hope you enjoy your stay in your warm welcoming home.