I don't see this as a basic tenet of Christianity (that minds exist independent of bodies), and I don't think it's an obstacle for any other religion that believes in a continuation of the self after this mortal life. The information accumulated from this life that constitutes 'self' could be transferred and translated to some other kind of existence. The next 'body' could be very different from this mortal coil.
There are a lot of problems with your points here, not the least of which is that most people, let alone Christians, do not buy the claim that mental function is dependent on physical brain function. But we know that the mind decays along with the physical brain in old age. What gets "transferred" from the ravaged brain of an Alzheimer's victim? Do false beliefs get transferred? Psychoses? And what physical activity drives the mind of God? If God can go brainless, then why can't people? I honestly do think that #1 is the most serious problem for belief in gods, because they are usually not thought of as material beings, yet they have the same moods, emotions, memories, and thinking ability of humans.
Religion is not science and is not meant to explain the scientific aspects of this universe. Religion is about our role in this universe, our relationship with God, nature, and each other.
This point is contradicted by a history of faith-based claims about our physical reality that have turned out to be dead wrong, including the idea that the Earth is only a few thousand years old and that biological diversity was essentially created as we find it today. Whenever there has been a contradiction between a religious claim about the material world and a scientific claim, science has prevailed. This leads one to suspect that revelation from a god is not a reliable source of information.
The interpretation of revelation depends quite heavily on the person receiving it. The light from the sun is the same, but it appears quite different when it is intercepted by a stone vs. cut diamond vs. the leaf of a plant.
Whoever receives it, it still seems to be as reliable as pure imagination, which is what I think it really is.
Prayer raises all boats together.
Actually, I can think of no human endeavor that has failed quite as often and quite as miserably. Christians appear to fare no better than adherents of other religions. If any were praying to a true God, you would think that we would see some kind of differential effect.
Because a miracle is, by definition, something outside the bounds of science and human control, it is no surprise, and no damning evidence of failure, that miracles are not corroborated by science.
Every miracle is a physical event, which makes every one a potential subject of empirical (a.k.a. scientific) investigation. The reason that people talk about miracles is that they see them as evidential corroborations of faith. They are not "by definition" outside the bounds of science. By definition, they are within scientific bounds. When the Vatican finally permitted 3 independent labs to carbon-date the Shroud of Turin, all three came back with independent confirmation that it was a medieval fraud. Why did someone bother to create such a hoax? Well, people needed, and still need, that physical corroboration of their faith.
Because reason #1 is the least relevant to religious faith or the existence of God, I'd say your argument is overall quite weak. Minds depending on this physical brain is not a no-brainer.
Mind-body dualism is a foundational belief of most religious faith, not just Christianity. Souls are thought of as immaterial spirits that can exist independently of bodies, and souls are very much in evidence in Christian literature.