Hmm. Their order page only lists a Holmes dj, and they mention that they're participating as an XMFC circle, so I think those are the only two they'll be bringing.

As for the password page, the hints are:
ID: birthyear of the one on the left of the picture
PASS: eye color of the one on the right

I assumed they were talking about the front page, Sirius and Harry? But that combo didn't work for me. :/