Forgive me if I talk too much. I guess i posted many posts after last night, just over-excited..
Ur daughter's stats is truly amazing, and at least I was surprised she was deferred by Y. I truly mean it, not just saying nice words to let you feel happy.
However, I have noticed two things that I would like to remind you. Forgive me if the words make you un happy.
1. As a friend mentioned below, you better ask somebody to check the essay for ur daughter. It is highly unlikely, but possible that her essay has some major problem. If not fixed, it will hurt her RD.
2. I understand ur daughter and u as her parent feel frustrated, or even angry with the results, especially after you saw/heard that some other kids with weaker stats get into Y or other top schools. i would like to remind you, from ur post, you sound like "my kid is so good, if you do not want her, others will want her". It is surely ok think in this way toward Y. However, if your daughter uses this attitude to write an application essay for other elite institutes, it would be very dangerous. The AOs are not smart, but usually are very experienced to sense the feeling behind the words. They need to see the chemistry.
Just my 2 cents. Like i said, i was just over-excited, and posted many posts since last night. If u do not like what I wrote here, just forget it.
Good luck!