It was a fun pleasure to work on your project. I hope I gain your and Giulia's satisfaction:)
Since you have asked for a flat easy to manage and order, then the flat needs as much storage area for little and big things as possible.
In furniture layout you can see that you have enough storage area for yours and your guest's shoes so no need to hide extra pairs under bed:). In the master bedroom the bed has one whole storage for iron boards or blankets,... . The other storage is bench by the bed and the drawers. The walk-in closet may need custom size shelves according to your needs but it has the advantage of being hidden that is again easy to manage and order.
In Giulia's bedroom another bed for her friends could be fit but to have one more bed, it is only possible by having a sofa-bed in living room for an extra guest.
All the spaces designed here have at-least minimum necessary standard dimensions for long term living comfort. you can use different size of furniture and still be able to fit them into the designed spaces.
Wish you the bests for you and your daughter in your new flat:)