First, let discuss about main blind windowless room. I just could dedicate any kids room to be blind room, so it will be your, parents room, blind one.
You will spend some time more in living/ dinning area, and they need natural light for homework, study, etc....but that is not tragic, as you could place high windows in both walls of your room which are the walls of kids room, also.
From the height of 2-2.20m till the ceiling, you can make the windows, and you will have enough light for basic activities. Not for late afternoon reading, but you will not be in the full lack of the natural light.
The worst scenario would be to have one kid with natural light and the other one with blind room. That would be terrible, I am sure.
There are also another one blind room, small one, just in the entrance of apartment.
That could be storage room or study or small office room.
Kitchen, is not huge one, also as living and dinning area, which are not big and huge, but just fine for your needs.
I think that it would be all I wanted to forward you too.
Have a nice reconstruction works and nice cozy afternoon and evenings in your new apartment.