Thanks for your opinions everyone!
After rechecking costs, it's approximately $45k/year for McGill (but 3 years only), $60k/year for Emory, and $40k/year for GWU. I know I'm paying a lot as my family is in an odd financial situation (my parents are legally divorced but both support me, however my mother, the legal guardian, does not work and my father plans on retiring soon, hence my need to try to still minimize tuition). I'm applying for scholarships as well but I don't expect much.
For McGill, my main concern is finding research and intern opportunities, especially since its main appeal is being able to graduate in 3 years. I'm willing to take a gap year after graduation to gain more work experience, but I'm not sure how that will look on applications.
Emory is a great choice, but its also the most expensive and I don't know how well I can do academically. Considering Emory seems to be trying to attract Ivy admits, I'm most certainly not going to be at the top of my class.
I enjoyed visiting GWU, and based on merit scholarships I hope I'll be able to keep a good GPA, but the dorms seemed kind of rough and the cost of living in DC is high.