Taking any test won’t hurt your app. If it’s offered, take it if you can. I have no idea if they will waive the requirement. You need to email them and ask how to proceed.
Go to the forum home page on this website, there are MANY subforums. Have a look at College Confidential’s home page, because there is all kinds of advice available. Here is a link to the international subforum: http://talk.qa.collegeconfidential.com/international-students/
As far as demonstrating that you have those qualities, that’s the magic question. You have it, or you don’t. The colleges will decide. All you can do is ensure that your application presents as good a picture of you as it can. Don’t get fixated on the idea of trying to get into an Ivy League college. That is a great way to set yourself up for disappointment. Find a college that feels like it will fit you. Look at the colleges in the Fairtest link I posted. A college like Bowdoin is going to give you as good an education as Yale, and will be easier to get into. Don’t just assume that a famous name means a great experience.