This is my 3rd time applying to and being waitlisted at EVMS, and I have called or stopped into the admissions office at least 15 times throughout the years (Kerry in admissions has been super nice when I have talked to her). Last summer talking to admissions they told me that the IS waitlist was unusually slow, and that only 1 person was accepted. I have seen a handful of IS spots open up this cycle, so it is sounding like this year is more typical. Have you received any offers anywhere else? If not, I would work next year's application so you can get it submitted ASAP.
In regards to how the waitlist works, they match demographics. From my understanding, when a student forfeits their spot, they try to find someone with a similar background to the initial student: ie similar ethnicity, GPA/MCAT, Male/Female, graduate program experience, etc. Talking to admissions, they told me that they usually offer seats to about 1.5 - 2x the class size, and typically OOS waitlist moves more than the IS.