It's logically possible for a Christian physicalist to accept the existence of a non-physical God, who created a wholly physical universe filled with stars, planets, atoms, particles, humans and animals, etc. So I don't see a necessary entailment between a defeater for anthropological dualism and a defeater for the existence of an omnipotent spirit person. By "defeater," I mean an argument that overcomes/refutes another contention. So we can have one without necessarily having the other: God can exist without dualism being true.
1) A non-physical God exists.
2) A physical world exists.
3) Dualism is false.
These three propositions do not inherently conflict with one another. Hence, it's logically possible for a non-physical God to exist alongside a physical kosmos. By "dualism," I mean "anthropological dualism."
Secondly, pace my dualist friends, I wonder why we have to reject David Hume's three causal elements. While I don't accept Hume's take on causation, let it be sufficient to note that causes possibly take place within a nexus of relations (i.e., there are causal linkages).
The astrophysicist Paul Davies refers to "causal linkages" (networks) rather than ascribing causal potencies to objects themselves. For example, I put my foot on the accelerator, and this event increases the velocity of my car. Therefore, I say that the cause of my car picking up speed is the act of pressing the accelerator with my foot. However, if there's no gas in the car or if some other factor prevents the vehicle from moving (no engine, someone stole all of my tires, bad spark plugs), then pressing the gas pedal will have little to no effect. For simplicity's sake, though, there's nothing wrong with insisting that pressing the accelerator (gas pedal) makes cars go, and pressing the brake with enough force causes vehicles to stop. Yet it seems that there is a causal relationship which exists between event A (pressing the gas pedal) and event B (the car picking up speed) to provide the glue that joins them; different causal events likely will not make my car go (i.e., the event of pitching a baseball or the event of opening the door to my house). By the way, Immanuel Kant wrote that cause-effect relations are not analytic a priori, but synthetic a priori whereas Hume suggests they are synthetic a posteriori.