I know nothing of essential oils (never used them or dealt with them), but from a chemistry perspective, I would be concerned that they contain residual solvents and other chemicals.
Because these oils are not food or drugs, they don't have to conform to FDA standards -- that includes the FDA's strict ingredient labelling requirements. Sellers of these products aren't required to disclose or test for what's actually in them (or potential chemicals in them carried over from the manufacturing/extraction process of the oils).
I wouldn't recommend using it in the same room (or enclosed space) as a rabbit or other pet, but otherwise I wouldn't expect it to cause harm to companion animals. However, if the rabbit exhibits any change in behavior or temperament, I would reconsider the oil's use in the house.
