Dear Client,
I present to You 2(two) variants of architectural plan. At first variant kitchen is more open, at the second variant is close to the variant 3, which you upploaded. I switch kids room with the master bedroom( as it is your desire for bigger area for kids ). At master bedroom there is a big bed(160x200 or 180x200) and 2(two) big wardrobes with sliding doors. Kids room is big enough to put 2 single beds, or bunkbeds, a lot of wardrobes, bookcases and storage units, and still there is a lot of place for the kids.
Floor everywhere is wood, at bathroom you can use tiles with wood textures.
My Best Regards.