Are you sure there are really 2 seperate seminaries? I was under the impression that it was called ateret in the past but people started calling it ateres in the past years as it changed over to BY. I really dont think there are 2.
It sounds crazy for a girl to apply to both darchei binah and ateres, but I feel like it may not be as crazy as everyone thinks. Both seminaries are warm and very growthful. If a girl fits this description, plus is willing to follow the rules of tznius and curfew, ect she will probably be good for ateres. It is a huge mix, and there were girls on all ends of the spectrum, but they did follow all the rules of a BY school.