I decided it's more important that you know what I was saying in the last note than that you figure it out for yourself*, because of time constraints. So I want to make sure you understand the distribution of the applicant population. In the general population, the distribution of talent** is presumed to be normal:
But the application pool is NOT Normal. It's the far right hand tail of that distribution (excuse the sucky drawing skills):
Harvard has the lowest acceptance rate (5.9% http://money.cnn.com/2012/03/30/pf/college/acceptance_rates_ivy_league/index.htm) in the US,so we'll use Harvard for our illustrations. Harvard has a class of about 2000 kids,which means the application pool is about 34,000. Now that's a huge number, in one sense. But's its a tiny fraction of your birth cohort's 3.9 million (http://www.infoplease.com/ipa/A0005067.html)***---less than one percent, 0.87%.
So what the application pool looks like is the very far right hand tail of your birth cohort, about three standard deviations out, like the drawing. The typical (median) applicant doesn't get in; the median is well to the left of the acceptance line. There are lots of applicants right around the acceptance line--and the really really talented kids (like the guy you know at one the elite colleges, for instance) are not typical, but rare, out on the far right tail of the applicant pool.
So if you're not a long shot (and I don't think you'll find anyone who says you are) then you should not be misled by the low acceptance rate at the top Ivies. At worst you're in that group that makes up 40-50 percent of the class that are just on the right side of the acceptance level or are just on the left hand side. In your case, your secondary characteristics (bilingual, time in Africa, European raised) mean that you'll enrich a class more than someone with identical talent who happens to have grown up in Bergen County, instead of Maputo. Admission officers like a diverse class with kids of different backgrounds!
Finally, it is a HUGE mistake to think of the distribution of MIT's class as being a bell curve with the genius guy you know there as the median student. First, it's not a bell curve--it's the far far far right hand tail of your cohort's bell curve, so it's more like a triangle. And, second, kids like him are on the far right of that curve.
In Major League Baseball, the same logic applies. The blue line in that case is called "the replacement level." The guys just to the left are in AAA and the guys just on the right are on the bench in the majors, but are essentially interchangeable--a GM could replace a bench player with a AAA player without affecting the team's performance.
As you think about optimizing the application process, I hope you'll keep this in mind.