Hi there,
Thanks for posting and CONGRATS on that stellar GMAT score!
You have a lot of things going for you, including the GMAT, great academics, CFA level III, and starting and running your own NGO for some time now is quite interesting and impressive; more info on that should definitely be included in your applications. Sounds like you'll have some good recommendations.
I wouldn't be too concerned about the lack of international experience; you've at least traveled some internationally which is better than some, and at this point not too much you can do about that.

Focus on what you CAN contribute to the class based on your life so far, professionally and personally...what about you and your experiences is unique? Think about it from that standpoint.
One thing you could also focus on is the fact that engineers can be stereotyped, rightly or wrongly, as overly technical, with weaker communication skills, leadership/management skills, overall people skills. So work to combat that by highlighting leadership examples; ways that you work with others; times you've influenced or motivated others, etc.
In terms of adding safety schools, how about Rice or McCombs given your energy sector interest? Haas is also great for that and somewhere in between these and the schools you've mentioned.
Let us know how else we can help, and good luck to you!