The ground floor is very similar. We have a total of 171m2 for three people and it’s great to live in. I also added the kitchen (still not all cupboards filled with the wife’s stuff, 2x bar stools, table with 6 chairs and couch). I would build the ground floor the same again except maybe make the window by the couch to the north side bigger than 1m to better see the garden from the couch. Vestibules? Usually the air is calm with us except when it thunders and hails outside sometimes but then the exterior doors usually stay closed. If you have controlled residential ventilation, the windows are usually closed as well, so there is no draft/doors slamming etc. Openness without doors was our premise. I’ll leave out the upper floor because we only have one child and the second bedroom serves as an office. Oh yes, downstairs in the northeast is the guest room or playroom, because the first child’s room is always so far away (upstairs) to tidy up.