Alright dude.. things look pretty good for you. Schools tend to LOVe candidates with a long history of non profit work and they tend to love candidates who want to continue in that line too. As for your goals, unless you have something concrete you are working on, you may want to think of going a bit more "conservative" and joining an already existing nonprofit, and laying your goals out there, because non profit is hard enough already.... it can help your chances out.. but that's up to you.
As for your school choices: why not? You have solid grades a very good GMAT, and wat seems to be good work experience. If you are testing 760 consistently and believe you can do better on the GMAt why not take one more stab at it? You have an awesome grade already, but I won;t pretend that getting a 760 won't help even more. Plus you have the luxury of time...
Anyhow your profile looks nice and solid, you are ready to apply!
If you like the post, give it a KUDOS!