I don't understand how the universe can be called infinite.Hmm..that's an interesting point. Although I still think that you can have more than one infinities. The easiest case would be to have multiple omnipotent beings create the universes of the multiverse (maybe each creates one and so on). But talking about our own universe, as far as we know, it has 3 space and 1 time dimensions, is flat, and is unbounded. All 4 dimensions are infinite, or we would have measured the curvature of the universe. So by your definition, there cannot be an omnipotent being as the creator since the universe is itself infinite? Am I interpreting this correctly?
I haven't thought that much about this point in particular but my first thoughts are as follows.
At one point there was nothing except God, then he created the universe in the big bang.
The universe started as nothing, or as a singularity, whatever you prefer, and the started to grow and grow.
I'm pretty sure that doenst mean its infinite, it just means its expanding.