Just found this site and stumbled onto this topic. I think you have all moved on from the shape of the universe but my understanding is you are talking of a 3D shape i.e. sphere. The nature of the universe is at least 4D with time as the 4th dimension, and possibly more yet discovered dimensions. Therefore the shape may not have sides edges or boundaries and I could not describe how it looks.
With regards to what was there before, something which is so small it is considered nothing, as something very large can be described as infinite. By definition the size can never be measured, so in the case of infinitely small, it is described as nothing.
As science progresses the smallest items become finite, that used to be nothing, until the smallest object that started the universe is found it will always be nothing.
As for the religion concept, faith is the belief in the unproven. In the past it encompassed science we have now answered, that which is still undiscovered but requires an answer leads to faith. Be it hypothesis, a greater being, etc.
The question of a greater being, leads to the question where are they? what are they and what existed before them?
