Hello!
For my proposal I've taken into account your requirements:
- open space
- bathroom with double vanity, open bathtub, WC+bidet, shower
- enclosed space for storage in indicated position
- enclosed staircase for noise reduction
- maintaining fireplace position
- maintaining drainage pipes for bathroom

Main challenges were:
- creating an open space with an ample linear view between the tub and the bed
- creating an intimacy gradient trough the space
- combining the warm look of the wood with the cold materials of the walls so to create a modern space that fits the existing old building
- finding a coherent lighting solution that unites the areas
- avoiding collision with structural wood elements
- access door that is not obstructed for the enclosed space
- finding a flat area in the roof structure where to install the glass slab and walls
- avoiding low height under the roof
- keeping the light source in the middle
- possibility to mount TV in the sleeping area
- possibility to increase or enclose the wardrobe.
- creating intimacy upon arriving up the stairs (discreetly hiding the bad and bathroom in the first glance)

Hope the project meets your needs.
All the best!

PS. the position of the wood elements needs to be verified trough detailed measurements. The solution is made in such a way that it can be largely adapted on site.