The Rabbit's Foot

The rabbit's foot Henry gets from Justin and gives to Serenity is meant to serve as a symbol of good fortune. While Justin likely thought of this trinket as a good luck charm, for Henry, it is more symbolic of his own true nature as the trickster out for revenge, which he did achieve by killing David.

The Fiddle

The fiddle (which Birdie teaches to Lucy and Clemency, and which Lucy later uses to busk) is symbolic of the voice of their human player's inner spirit. This can certainly be said for Lucy, who uses her fiddle as a means to make money. However, she is clearly attached to her fiddle and, when she has the money to do so at the end of the novel, chooses to become a professional musician. This illustrates Lucy's desire to finally express herself; she cannot do so...