Calmom, you just nailed it. Writing their essays was just a theoretical task until there was practically no time remaining. I think both kids got more of a sense of what their application told about themselves after it was 90% finished. That’s when they sat down to write autobiographical essays.
Our son began his with a sentence about the Three Gorges Dam project in China, and how that topic – far from the USA – became a case in his policy debate that year. He generalized that to what he learns from debate, on topics far from his everyday experience. And he expanded that into his other extracurricular activities and interests.
Our daughter took the approach of explaining why she liked to watch and talk to people who are looking at her art products. What she learns, what art means to her, and why making art is aimed at other people, not mainly an egoistic endeavor.
So yes, under the gun, near the end of the application process, the applicants can lay out their self-descriptions, their aspirations, and how they like to spend their time. This brings the summaries of extracurricular and curricular activities together.