Ah, I see your problem. You hear "God" and you think of a humanoid being floating in space. I hear "God" and I think "everything". It's merely a matter of semantics. Intelligence, self-awareness, consciousness. What is the source of these? Your brain? Your brain is made up of individual cells (which, in turn, are made up of atom, and so on). Is a brain cell (a neuron) intelligent? The cells themselves are not directly aware of the brain's intelligence, yet they act and react to the brain's whims sometimes in concert with thoughts, sometimes independent. What if intelligence and the rest exist outside of the material universe? Why couldn't the universe itself be intelligent and the individual parts are merely facets of that intelligence?
No, we do not accept the universe has always existed, we have caluculated the approximate age and we have no knowledge of what existed for what period of time prior to that.
It is possible because anything is possible, but there is no evidence to support the probability of the existence at any point in the processes.
Or not. There is more evidence to oppose such an hypothesis than to support it. It is the lack of evidence or even rational explanations that make such a position difficult to defend. What if the universe is the dream of an entity and what we believe exists does not in reality? There are more "what ifs" than one can count in a lifetime, but the ones with some level of supporting evidence are few.
Possibly, we as humans think that way, but there are many possibilities as to what may or may not have been. According to some theologies there was nothing in the beginning too.
Careful. People might begin to think that you are agnostic. What if 'god' is a construct man created to cope with not being able to understand the universe?