I think you'll be fine. Just try to relax. If Kathy Williams says that your file is complete, then your file is probably complete. As for when they'll send out acceptances, I think the three week estimate in your email is pretty accurate. I applied last year and didn't find out until the last week of March that I was wait-listed. I'm pretty sure they told me when I called that they had just finished reviewing applications the week before.
I just have to say that your results post about receiving an update email really freaked me out! I knew I hadn't gotten an email, lol.
Oh, and my track is Film Studies. I'm glad to see that there aren't very many Film Studies people on this thread. I got the impression last year that an overabundance of film applicants thwarted my chances.
Good luck to everyone!