Dear all,
To give some "peace of mind" (however possible that is during this process): I called the admissions office this week and they've said that while those April dates are the last few interview dates so far, after April, they will take another look to see whether they would like to add any interviews in May (that is, no guarantees, but it is a possibility).
As for those of you interviewing in April, yes, there have been plenty of acceptances given out, but I was told that according to their statistics, many of those acceptances may not be matriculating. So, those of you who are interviewing in April are not necessarily interviewing for "waitlist spots". Again, while their class could be described as full, since schools accept more than just the number of class spots (here probably about 2x as many seats), there are still more acceptances to be handed out.
Hope this helps. Probably won't be able to know much more until a week or so into May.