Christianity and Buddhism fit together very comfortably. I’ve found great meaning in the integration of the two. That being said, we tend to create our own heaven or hell with our emotions, thoughts, and beliefs while we live. Heaven and hell are subjective. There are constants in the universe, just as there are in math and science. The unconditional love of God is one of them, law of attraction is another. You can remove yourself from love by focusing your life on negativity and things not beneficial to compassionate coexistence and in the afterlife you could find yourself in the dimension of no love depending on how deeply invested you were in those emotions and beliefs, and what you attracted to yourself. There is no red guy with a pitchfork waiting to burn you for eternity. But free will gives you the ability to screw yourself quite thoroughly. We are all eternal beings, so as individuals we have all eternity to figure it out. And yes you’ve lived many lives and have many more to live. For most people there is a reviewing and learning period in between lives. Some do come back immediately to attend to unfinished business, but that grace period between lives is more the way it goes. I love that you question traditional beliefs and consider possibilities, that is where truth is found. Refrain from passing judgement on others, they must learn from their mistakes as we all do. Trust your instincts, they’re good.