You can be pre-med at all of those schools.
The committee letter thing is worth looking into. Some schools give a committee letter to all applicants who want one, as long as they meet certain deadlines and requirements (not requirements like a certain gpa or mcat, but have taken all the pre med classes, had their interview with the committee by a certain month, etc).
Seems Duke has a similar policy: https://prehealth.duke.edu/apply/letters-of-recommendation/types-of-letters-of-recommendation/committee-letter
Actually it seems JHU does too: https://studentaffairs.jhu.edu/preprofadvising/pre-medhealth/applicants/eligibility-for-a-committee-letter/
WashU’s is not clear to me. https://prehealth.wustl.edu/pir/Pages/default.aspx