Medical schools can also employ medical researchers and operate hospitals. Cornell and Dartmouth were the only Ivies I came across that participate in holistic review but my list is by no means comprehensive (I did not do a systematic review of all schools) so I can't comment on Harvard or Yale (although I would suggest looking at their admissions pages - you can usually get a good idea of their admissions philosophy there or sometimes through their Twitter or Facebook accounts).
Following the permanent registration with the medical and dental council, doctors can specialize in any of the various fields that is organized by either the West African college of Physicians and Surgeons or the Ghana College of Physician and Surgeons.
Finances: Although it's nearly impossible to graduate from medical school without some debt, you don't want to accrue a lot of it. Whether you owe $50,000 or $300,000 when you're done with your medical school education will have a long-term impact on your future.
The other thing about attending medical schools and using the distance option is you don't get the benefit of other people in the classroom debating and even asking spin-off questions from yours that you didn't think of. Studying with other people in your class is certainly helpful and makes things easier, but often in distance learning settings you are on your own other than the schools' support sites, phone numbers, and reading materials.
The only obstacle is that a residency program would have to sponsor your H1-B visa in order for you to be able to work as a medical resident in the US - which can effectively increase the competition among the international students, as spots like that are somewhat limited.