In my opinion, it is impossible to accommodate two children in children's rooms that differ so much in size. You will have to listen to the children's reproaches for years about how unfair it is. I would also do without the guest room on the ground floor, because a 24m² living room is really very small. If absolutely necessary, you can always put up a wall, but your house would be too small for so many people for me. I would definitely enlarge the kitchen; for a family with two children, I also find it too small.
Best regards
Sabine