I would personally swap the position of the staircase with the entrance hall; currently, right after entering, you are immediately facing the bathroom door o_O. Further ahead, the entrance area could perhaps even be integrated into the desired open floor plan, and I wouldn’t see it as a disadvantage if the staircase to the basement were a bit further away from the living area. Many people would gladly pay for a possible south-facing orientation like you have. :D Perhaps the pantry/storage room could also be moved further forward or even omitted entirely to make a bit more space for the bedroom. Again, I find drawing in actual furniture absolutely essential!!! The basement bathroom with two doors is unfortunate, and the rest of the basement layout seems unnecessarily convoluted. Maybe you should free yourselves from the idea of giving the rooms too many functions; the planned use as a separate apartment brings design disadvantages. For example, depending on the age of the children, we moved our bedroom from the ground floor to the basement, so maybe you completely banish the ground-floor children’s room or consider such a later switch between parents and children. A piano against a sunny/exterior wall could be tricky; I can also imagine a music room/area very well in the basement. I don’t know if you’d actually use a window seat with these window fronts — basically, the entire open living area is a window seat. :D The basement could have a generously sized terrace under the balcony and in front of the bedroom/children’s room; it would also be conceivable for me to move both parents’ and children’s bedrooms completely to the basement, provided you get enough windows there, and have a larger office/children’s room on the ground floor. In general, I would keep this possible switch of sleeping rooms in mind because I have experienced it myself and found it good. Renting out to strangers would be a very distant consideration for me, and I wouldn’t ruin the floor plan because of it. With the large balcony, I can very well imagine that people won’t go into the garden to barbecue, etc. My niece, for example, has a similar setup; they have a side staircase to the garden, and we always sit nicely elevated on the large terrace/balcony — but this has to be generous in size.