Now that I wrote this, Eva and Cora are two similar names aren’t they ? I wonder what the meaning of Eva is !?
I think the name Eva is pointing to the biblical Eve who fell from paradice (perhabs into Wonderland 😉 )
Cora as her sister is standing by watching Eva get everything she wants, the prince and the kingdom. She is jelous and lures her sister into her demise like the snake in the apple tree. Maybe Reginas tree will come in to play her. It’s a tree from her childhood garden, maybe even from the sisters Cora and Evas childhood garden. Where Cora poisons one of the apples.