I do not like the idea of 'one offs', and because we do not have any evidence of there being a God, I believe in the theory of universal birth, death and rebirth.
all your questions and answer to them are contained in above statement of yours
there is no evidence of GOD and there is no evidence of big bang either, only hypothesis.
you believe in reincarnation- so did you choose to be a human, if you don't know then some one must have forced you ? that some authority is GOD.
i am replying to your post, also because GOD wants to tell you that He exists and if you so desire he shall communicate with you via medium of your choice.
GOD s messenger