First objection: Necessarily, nothing can create concrete objects ex nihilo. So the posterior probability of the fine-tuning of the universe of concrete objects on the hypothesis that the god of classical theism both (i) designed it and (ii) ultimately created it ex nihilo is nil. But according to classical theism, for any world W containing concrete objects, God ultimately created the concrete objects in W ex nihilo. Therefore, classical theism entails that God ultimately creates ex nihilo any world containing concrete objects he designs. Therefore, the posterior probability of fine-tuning on the hypothesis of classical theism is nil.
Second objection: There are final causes in God's nature that are ontologically prior to his intelligent agency. For example, God's intellect and will work together to perform various functions, such as designing and creating things. God's life is also meaningful and purposeful according to classical theism. On classical theism, therefore, final causes are built into God's nature without a prior cause. But if that's right, then classical theism entails the existence of final causes at the metaphysical ground floor that God cannot create. And if that's right, then theism entails that non-conscious teleology is a more fundamental feature of reality than teleology caused by intelligence. And if that's right, then we'd expect base-level teleology in the universe that's not caused by God on the hypothesis of theism. Therefore, absent a further reason for thinking cosmic fine-tuning isn't expected unless caused by a divine fine-tuner, cosmic fine-tuning doesn't confirm theism vis-a-vis naturalism.