I think there's a disconnect between the terms "IMG" and "FMG". I always took "IMG" to mean Americans who went outside the US to go to med school, usually because they were not good enough students to get into a US MD program, and usually ending up in the Caribbean. FMG I always took to mean people from other countries who went to med school in their own country (often very strong schools) and applied to residency in the US. The latter is usually regarded more favorably than the former, barring any visa issues.
The programs you listed are mid to low-ish tier places but not bottom-feeders. Just looking at one as an example - SLU - I see a lot of people that look like FMGs, and only a couple of US-IMGs from Caribbean programs.
What I've noticed is that neurology as a specialty has more international prestige than domestic prestige. Prestige in the US is much more weighted for how much money you can churn out, with people that can do 30 of the same simple, highly profitable procedure in a day being at the top of the heap. The bottom of the heap is the lowly cognitive worker that spends extra time with an undiagnosed problem seen by 10 specialists already and eventually comes up with an answer after being up all night thinking and reading, because nobody's paying for that ****. Internationally, where income and procedural volume are not as tightly connected as in the US system, neurology is more highly regarded.