Statues
There are a total of six statues, two groups of three.
As the post below explains, the identities of one group should be obvious: the girl, the jester, and the magician from the folio and the rest of the mirror world here.
The second group of statues, hmm. They don't have heads, but they all seem familiar nonetheless. All females. One with two moths/butterflies. A second, younger, with a poppy. The third, older, standing on a skull.
Unclear what the significance or utility is though, apparently.