Be A Longhorn Twitter addressed two questions often posted here - second choice majors and whether the number of people already accepted from your high school matter.
“Do you accept a certain amount of students per high school or does the major you apply to affect the admissions decision more?”
“Each application is considered on its own, and for the first-choice major to which you’ve applied.”
Looks like this year will be like last year where those admitted to the school but not to their first choice major were allowed to choose from any open major.
And someone in your high school getting in does not decrease your chances.