deegee,
What you are saying is that God will protect you from demonic attack, but he won't protect you from other life threatening, fatal situations? Why is God's protection so selective? This doesn't make any sense to me.
You still haven't arrived at a conclusion that he exists, so how can you question what doesn't exist?
But you can take Paul's example. God didn't prevent his suffering, not Christ's, nor many of the thousands upon thousands of Christians executed. They happily went to their deaths. Suffering != God's inexistence, so you're going to need a better argument.
(5) How, exactly, does an immaterial spirit interact with a brain and body of matter?
What force or causal influence does it exert, and by what mechanism?
I'm not sure. Just because I can't explain it doesn't mean it doesn't exist.
I have not experienced many of the symptoms you have related. When I pray, I don't receive a vision or anything, just peace of mind and comfort. If I've sinned, my conscience draws me to repentance and to confess my sin to God.