ᐅ Floor Plan / Design of a Single-Family House with a Secondary Apartment on the Upper Floor

Hello everyone,
we are currently focusing more intensively on the topic of building a house.
Therefore, I would like to present our floor plan and thoughts and I am looking forward to your feedback!

Background:
My wife and I currently live with our daughter in my parents’ house. My father lives above us, and we want to continue living in this arrangement. That means we need an apartment for us and one for my father.
Since we will need a barrier-free apartment for ourselves in the short to medium term and an age-appropriate apartment for my father, we considered renovation/conversion.
However, we ruled out renovation and conversion because the current building condition is very poor. We also contacted a local architect about this.
After visiting the house, he (although he normally focuses exclusively on renovation/conversion) came to the same conclusion. In his opinion, renovation/conversion would probably be more expensive than demolition and building new.
So that’s what we did. After several discussions with different companies, we ended up with a local masonry builder. A small company in its second generation with employed masons, where we feel well taken care of.
We already had a desired floor plan in mind and, together with the builder, the attached floor plan was developed. Overall, we are very satisfied with it. Financially, it looks good, and we even have some room for small extras.

About the sketches:
We are currently waiting for the new drawings from the builder.
The ground floor (GF) will be as shown in my sketch below. The upper floor (UF) will be larger, but the room layout will remain the same.
The house will be positioned parallel to the street, with the front door facing the street.

Now I am cautiously looking forward to criticism, questions, and hopefully lots of input from you!

Development plan / restrictions
Plot size 23.5 x 40 m (77 x 131 ft)
Slope no

No development plan

Client requirements
Style, roof shape, building type no special requirements
Basement, floors no basement; upper floor with 1 m (3 ft) knee wall
Number of people, age 4 (31, 34, 2, 62)
Space requirements on GF, UF main apartment completely on GF
Office: family use or home office? family use + guest bed
Overnight guests a few times a year
Open or closed architecture unknown
Conservative or modern construction rather conservative
Open kitchen, kitchen island should be a closed room, preferably with a sliding door to keep the option open
Number of dining seats 6
Fireplace no
Music / stereo wall no
Balcony, roof terrace balcony if there is a secondary apartment on the upper floor
Garage, carport double garage
Utility garden, greenhouse no

House design
Who designed the plan? basic idea by us, drawn by the builder
What do you particularly like? Why? basically we are satisfied. We like the “attic space” that can be converted later as needed
What do you not like? Why? bedroom facing the street, we would prefer office/guest room, but we think this does not really fit with the room sizes
Offer from the builder: house 335,000 €; additional features 16,500 €; photovoltaic system 11,000 €; double garage 36,500 €
Walls and ceilings plastered to Q2 finish; tiles included, the rest additional
Personal price limit for the house, including features: 550,000 €
Preferred heating system: heat pump