Downstairs it simply gets cramped if all rooms are supposed to have a window, and I wouldn't want a bedroom, a bathroom, or a dressing room without a window.
So the design doesn't work like that.
Since the financial resources are apparently limited, you can't enlarge infinitely. So making the basement now so big that all rooms get a window there is therefore out of the question.
So I have to think about a different layout.
I would put living/dining/kitchen downstairs. Then the windows are sufficient, and you have the terrace directly in front of the dining area. Pantry and freezer room don't need a window. I would definitely plan a guest WC there, and if it doesn't get a window, that's not super optimal, but it works with good ventilation. But maybe you can squeeze it into the back right corner of the plan and bless it with a small window.
Plan children's rooms and an office with a bathroom on the ground floor. At the moment there is no second child yet, so one of the rooms will be a bedroom at first.
Upstairs, in the next few years, you can treat yourself to a nice master suite with a dressing room and wellness bathroom.
The kids (and the parents too!) will survive if the kids are not accommodated on the same floor as the parents. In toddler age a baby monitor helps and otherwise there is a staircase, not the taiga, to be overcome to check on the kids. My brother has three children, only one sleeps on the floor where the parents sleep. I couldn't determine that either kids or parents were seriously harmed by this (and it was the last child who then got a room upstairs by cutting off one side of the originally huge bedroom).
The layout also has the advantage that you don't have teenagers with their friends walking through the living area. I would possibly consider preparing connections for a kitchen in the office on the ground floor. Then you could even give the teens their own domain when mother and father aren't working anymore (and maybe a small desk in the parents' area would suffice), but the kids are old enough to take care of themselves.