In consideration of your needs, I have designed a bigger bedroom, Two smaller bedrooms for two sons. This shall have bed, desk, library and wardrobe . Two bathrooms in the same position as they are now , Living room/ Kitchen in an open space. This should be located at the entrance by breaking down the wall which now divides the first two rooms. In the open space should be placed: kitchen, table (basically for four but with the chance to extend in case of guests), TV corner, desk corner. The open space should have a minimal/ modern aspect.
It has been a pleasure to work on this project. Hope you like it.