Patnjali Yoga Sutras 3.18 "By making samyama on previous thought-waves, one obtains knowledge of one's past lives."
Bhagavad Gita 4.5 " Krishna said: Many, many births both you and I have passed. I can remember all of them, but you cannot, O subduer of the enemy!"
You have only proved that the theory of reincarnation is a legitamate theory that should be considered. Our dreams are a mixture of our past experiences and present desires. We are beings who seek the truth and answers. The fact that our mind and brain have an innate need to dream up past lives shows that there is grain of truth to it and it is a deep seeded belief. Past live impressions exist in our subconscious mind. Dreams and imagination express our subconscious mind.
Umm... No. People don't believe they have a relationship with God because someone trains them to or because they train there mind to do so. People don't try to deceive themselves. They believe they have a relationship with God out of there own experience.
Everyone dreams and everyone has nightmares.