You are still considered a "foreign grad" if you go to UWI. And, I would argue instead that the best Caribbean medical schools are actually in Puerto Rico. Nonetheless, all of them are still in the Caribbean.
Likewise, all non-LCME Caribbean students (at least at the reputable schools) do clinical rotations in the U.S. with, as was at least in my case, only 16 months total spent in the islands... despite it still being considered a "Caribbean" school.
All of which begs the question... what are the true distinctions here? Up-front competitiveness for admission? Is that it?
The cream always rises. No matter where you wander.
-Skip