The Presidential Scholarships at Wake Forest are for the arts: dance, music, theater, visual arts, and debate (Poor debate… not sure how or why it got lumped in here. It is probably based on its oratorical roots.) While you are a very accomplished student, but I don’t see a strong arts focus.
I think you should look at some of the other scholarship programs and push your involvement in Model UN. Thinking more about it… it might even be worth talking to admissions to see if MUN somehow falls under the Speech and Debate umbrella. In that case, you could apply for a Presidential in debate.