Considering your requirements and needs, and at the first place wish not to move water and drainage pipes and installations, but also with my vision of the most valuable using of space, I made two proposition for your apartment.

First proposition is with bathrooms on the same place as they are now. Here we have laundry area in front of bathroom 1, with enough space for washing and drying machine. Entrance area is divided from other part of apartment just with different floor covering. Apartment has day and night zones. Day zone consists of living and dining area and kitchen. Kitchen is separated and closed, and has natural light. Living room is close to windows so it also has lot of natural light. It is furnished with sofa, armchair, TV with TV stand, coffee and side table and bookshelf next to sofa. Central part of apartment is planned for round dining table with 6 chairs. Round shape is best for this organization of space because this is also going through area to living room. Day zone is separated from night zone with transparent screen made of narrow vertical wood panels. Here we have bathroom and three rooms. Master bedroom has big double bed (180/200), big bookshelf (can place TV here if you want, too) and walk-in closet. Child room has one-person bed, closet, desk, night stand, armchair and book/TV shelf. Also, there is another walk-in closet, or storage next to child room (this part of apartment is so deep and without natural light so it is best for storage/closet). Third room has double role. As here we have bed, shelves and desk, normally it can be used as study room and sometimes as guest room.

Second proposition needs some more works, but here we have much bigger living room, as it is expected for this size apartment. Living room is expanded to area of WC 1 and ante WC 1. It is furnished with big sofa (4 seat), 2 armchairs, big book/TV shelf, coffee and side table. This living room has even more windows and natural light. Kitchen is separated, with natural light and it is divided from living room with glass panel. This is just an option, and if you don't like it, it can also be normal wall. I planed direct sliding door from kitchen to living room. Dining area is like connection between kitchen and living room. It is big square dining table with 6 chairs, normally placed leaning to kitchen glass panel/wall. And if you have guests and need some more sitting space you can just move table and add some more chairs. All this was day zone. In central part is entrance area with closet and chair for footwear putting. Also, here is laundry area with washing and drying machine and ironing board. It is close to now existing bathroom so it will be easy to install new pipes here. Also because of this, new bathroom is planed next to existing one. Night zone is totally separated here. Child room has one-person bed, closet, desk, night stand and book/TV shelf. Master bedroom has big double bed (180/200), big bookshelf (can place TV here if you want, too), walk-in closet, armchair and makeup table. Between this two rooms is guest room.