I live in a three storey new build, but the layout is different to you and being new build the walls are paper thin. I doubt I am going to be much use to you, but this is the arrangement of our house.
Grd Flr - kitchen, playroom, cloakroom, lounge
2nd Flr - main bathroom, single bedroom, double bedroom, main bedroom with ensuite (where we are).
3rd Flr - shower room, bedroom (ds), bedroom (dd).
I like this arrangement, I can hear dd moving around, even when we are in the lounge which is two floors below her! Ds is loud anyway and if there was something wrong with him, we would know quite quickly. Also in the event that (touch wood) we ever got burgled hopefully dh and I would hear them first.
We were away in London over half term in another 3 storey property where 2 bedrooms were on the ground floor with a loo, lounge, kitchen were in the middle and then another 2 bedrooms on the top, this was an older property and I really didn't like the dc being on the ground so close to the front door and I felt like we were miles away from them as there was a floor inbetween us.
Could you have your elder dd on the ground floor and you on the top? Not so keen on it myself, but really can't see any other options for you.