I’d give the 6 year old boy, the 8 year old girl and 10 year old the largest room. The boy would have his own side decorated with whatever he likes… the two girls 8 and 10 would share bunk beds really cute and decorated.. my 16 year old would have her own room.. then there would be mines.. once my 16 year old went off to college then my son would get his own room and the two girls would continue to share a room.