Opinions on the draft

Do the parents also have to go directly into the garage?

No, they are by no means so old that they no longer drive a car (early/mid 50s)... The garage is also meant to store the trash bins and bicycles. Direct access is therefore quite practical. The airlock will probably also often be used as a connection between the apartments, especially by the children, to quickly visit grandma/grandpa.

Why don’t you plan the bathrooms on top of each other? Where is the south in the design (or did I overlook that?). I would definitely also separate your entrance from the parents' entrance. I know several who don’t have it and deeply regret it!

Why don’t you plan the bathrooms on top of each other?

Because it works better with the room layout that way. Switching the bathroom and the study/guest room on the ground floor would in principle be possible, but not very sensible. Exchanging a children's room with the bathroom on the upper floor would also be difficult due to the room sizes, etc... One could possibly place our bedroom/bathroom to the south and the children's rooms to the north, but then one child’s room wouldn’t have a “normal” window and they would have less light... so the layout seemed best to us.

Where is south in the design?

The exterior view is the south side. On the floor plan, therefore, to the left.

I would definitely separate your entrance from the parents’ entrance as well. I know some people who don’t have it and deeply regret it!

Yeah, we quickly agreed that we want to have them separated :)