Wow. Tough.
I previously relayed a story of a student who this happened to when I was in residency (at a U.S. medical school-affiliated program). In his case, there were clear psychological/performance issues. Here, it appears among other things that Step 1 was the big hurdle.
Having said all of that, I'm not exactly sure what you're hoping to gain by transferring to a Caribbean school. At this point, you'd still have to pass (as you know) USMLE before you can get into clinical rotations. Your best bet would be to call one (or all) of the reputable programs' offices in the U.S. and specifically discuss your situation. They may or may not accept you, and you will still have to pass Step 1 before you can start clinicals.
With regards to interviewing and matching into a Family Practice residency... it will depend on how you do during your clerkships, how you do on Step 2 CK/CS, and what kind of recommendations you can get.
It must suck getting dismissed from U.S. medical school. I feel for you. You have options. You've invested 2+ years of your life in this pursuit. And, if you're being honest with yourself (and us) about why you were dismissed - and are able to rectify those issues, then there's no reason why you can't finish your medical degree and go on to practice medicine.
Call SGU, Ross, AUC, and Saba's U.S. offices. And, good luck!
-Skip