You seem like you have a relatively good shot at acceptance but noone ever knows for sure.
I am curious about a couple of things:
From you: “Applying for Biochem and Econ in order to enter the biotech side of pharmaceuticals.”
This is a very specific career goal for a high school senior. How did you come around to this focus? What are the reasons for your interest?
And this from you: “Harvardś unique commitment to academic harmony in dual majors really appeals and makes it my first choice.”
What do you mean by “academic harmony”? Have you checked these two departments to look into joint concentrations and the requirements to do that? Some even require a petition.
There are many many schools that will be good for double majoring.
Harvard won’t give merit obviously. Have you considered other schools that do give merit? Including your state university?