I can't speak much to the program itself because I did not do that MS; I attended a different MS program. Merely from the viewpoint of utility, I think you would be better off w/ the MHN than the USC program. If it should come to pass that you are not accepted to medical school - its time to find a job. Unless you are applying to a very specific niche or have a connection to something, "Masters in Global Medicine" sounds like garbage on paper to an employer. MHN actually clues you into what the degree is in. The Global Medicine degree is as marketable as a MS in "Biomedical Science" - seriously, what the hell is that - its not marketable at all.
Depending on the grade-repair that needs to be done, a post-bacc may not be the most viable option - your post-bacc grades will get diluted with your old grades - so if you get a 4.0 in your post-bacc, it may not be good enough to get you over the cut-off GPA for a given school. Having the new, high numbers in a graduate GPA (which is calculated independently of your uGPA) will be seen at the onset (vs. a hypothetical 4.0 diluted into a 3.1 college GPA - your 4.0 would only be seen if it was looked for - no one is going to go out of their way to look for it.) Master of Science in __________ is a good way to go, and if the medical school application cycle doesn't play out favorably, you also have a marketable degree for the job market.