These are great questions and valid concerns. Could you tell me the percentile breakdown of your quant and verbal scores respectively? If your quant is over 80th percentile, then you're fine. And if it's pretty close to that, I think you're still fine given your A grades in past math courses. If it's well below that, then you might consider retaking it or enrolling in a stats or finance class to show that you can hang with the finance kids
Honestly though, it depends on your own tolerance for risk! I think applying early decision will help a little, but it's difficult to say whether it would be enough.
I think you've got a shot at Columbia, but I'd say it's a slight reach. You should definitely apply, but I think you should also apply to some safer schools. While you're definitely really well-rounded and have a very global perspective/experience, I don't see a whole lot of leadership roles in your experience. That is something you're really going to want to focus on in your application - highlighting your capacity for leadership, both inside the workplace and outside of it. Think about times when you've led or managed teams (formally or informally), when you've initiated a new project/service, when you've challenged traditional thinking/ways of doing things.
My advice is to embrace your current profile and showcase it as best you can in an early decision application. Of course, that is just my opinion - you'll have to make your own decision at the end of the day
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