DO schools often look for DO-philosophy adherence in the applicaiton. They dont want to be someone's backup (even though that happens probably more often than they would like to admit).
I tried it that way and actually got wait listed at the DO school backup but accepted to MD schools.
if DO is still an option for you make sure your resume reflects it (DO shadow and letter). and DO is a much better option than Caribbean just due to the lack of licensing obstacles. DO education is far superior to carib. schools IMO, but the boards are the great equalizer so school selection has no intrinsic bearing on the individual. if you can pass then u are good enough by our standards.
you could also take a couple years to do MHA, MPH, science masters, grad school in general.... these things look good and can make the difference if you are on the cusp.
also, simply reapplying can have a positive impact. the schools pay attention to the number of applications and coming back to them shows you are dedicated. If you get waitlisted at MD and that is what you want then I would say take a year to gain some life experience and try again.