Red Queen Coat. Underneath it she's wearing her ivory wedding dress. I love the collar detail she's added, which gives the coat that little bit more of a Queen of Hearts theme.
Given the threatening poses (and the rather splendid axe), I suspect the words Off With Their Heads were uttered at least once. Which is as it should be.
A few more photos under the cut (including a group shot in which there appears to be more than one visitor from the Lewis Carol canon).