You probably won't like this advice, but in your situation, I would reapply next year, and focus on programs that offer funding. If you are interested in doing Modern and Contemporary, then definitely apply to Williams, as they are very generous with their funding (at least in my experience) and have exceptionally high placement rates, both in curatorial positions and academia. You will have trouble getting a curatorial job with an MA from Christie's - most of the people I know who have gone through auction house programs are working either in the marketplace or have various other art world jobs (like communications and social media staff at museums and galleries). You may still have trouble getting a curatorial job even if you go to the IFA, because curatorial (outside of contemporary) is largely a field where one must have a PhD if they wish to succeed. In either situation (Christie's or IFA) you will be spending a ton of money for minimal career and professional returns, especially if you have no idea what you want to do professionally. IFA has a great PhD program (and networking opportunities), but it's not worth funding those PhDs by getting your MA there, because you won't get the personal attention that MAs in other programs do.