Hey debayan222 - Happy Independence Day to you too and thanks for the question!
We hate to do this to you but... we can't really answer the first one. That's for you to find out in your research for Columbia Business School! If it wasn't literally an essay question that they've asked, we'd be more inclined to answer - 'cuz there's a lot we could say about that.

We can say that Columbia has a strong real estate program, so you're being smart by targeting them for that. The NYC real estate market is something to explore - it's a bit of a different animal compared to economies and markets in other cities. You'll need to do some digging in terms of job prospects - and obviously it totally depends on what you intend to do in RE since it's a very big category.
You have the right idea, in terms of hitting people up for their opinions and insights - that can be a great way to gather some info about this school and the city. If it weren't for our pesky policy of never telling people what to write in their essays we would surely be able to do more with it.

(The real risk of us answering a question like that publicly is if we do, then EVERYBODY WILL WRITE THE SAME THING IN THEIR DARNED ESSAY. It won't help you nor would it help them. And we won't answer a question like that privately 'cuz ... well, we just won't.)
Good luck with it! If you have another question for us not to answer we hope you'll post it!!!
EssaySnark
PS we're totally kidding, hope that's clear.