I thought south is almost west? So NNW? Then there is great evening sun. Children usually bother much less about noise than adults, but that is an individual decision.
Why do you actually need the storage room on the ground floor? It would be a great coatroom. But if it is only meant for storage, I would eliminate it. After all, you have a basement.
The utility/housekeeping room in the basement with almost 20 sqm is already very spacious, but you can certainly put shelves and cabinets in there for storage. Although I would divide it differently. The room at the top right (playroom, but probably a second office?) flush with the office. Extend the corridor a bit. If there is no direct access.
And if you want to place the terrace on the right in the corner as drawn, I would definitely move the light well of the fitness room upwards according to the plan.
Show the facade so one can see how changes would affect it.