I guess for story purposes, I think even the concepts of beginning and end, of start and finish are based on human perception of space and time so are irrelevant when proposing ideas about the coming to being of creation.

Existence has no requirement to fit our understanding. We could have been entities which existed in higher dimensions, but were put in the toy box of 'space-time', and in the blink of an eye from the higher dimension have generated what we consider to be reality out of the concepts of language and pattern recognition.

The big bang could have been the opening in which the higher dimension remnants poured into the toy box, and everything that came forth was a consequence of those elements attempting to reform the nature of the higher dimensions, while being limited by the constraints of space-time.

Of course that's all speculative, but I think that's part of the joy of life, speculating. Science starts with a hypothesis, so we must keep in mind that speculation is actually the beginning of science.

(Rigorous practice, analysis and critical reasoning of the data collected is of course the body of it.)

• TL:DR; I'm procrastinating other work, so I've spent too long enjoying the thought of alternative realities.