I have been waitlisted at UArk - and I saw someone else was too, so I wanted to give a quick update as I just had a chat with one of the professors there.
I'm sure all schools are different, but in this case they said there is no ranking of the waitlist, and that the decision of who will be offered a spot is highly dependent on 'fit' with the other incoming student - in other words, they only accept two people into this department, so they want the pair to be compatible. It's not something that I thought of as being important, so I hope this information is useful and comforting to anyone else out there waitlisted - I know it's impossible not to take it personally, but there are so many factors beyond the quality of your work/your personality/whatever else you are picking apart.