The absolute absurdity of God

[SteveII]

I really, really don't understand this rabbit trail we are going on and how it relates to any part of any argument, but...

So an infinite spacetime, in this vacuum state is always in a constant production of particles and fields. What's keeping this mechanism from popping a Universe?
No matter how unlikely it actually is, in an infinity of spacetime, it must surely happen... perhaps even an infinity of Universes are bound to happen. Surely, not all at the same point of spacetime.

You continue referring to spacetime as something other than a model of the real things it describes: 3 spacial, 1 time dimensions. Spacetime is not itself a concrete object. When you propose that spacetime is infinite, that is inaccurate. You are proposing that the 3+1 dimensions are infinite. These 3+1 dimensions are bound in our universe--a universe that by most accounts had some sort of beginning. So, talking about anything outside of our universe is pure metaphysics where anyone can dream up anything. The problem is that dreams have to be internally consistent. 

If this magic quantum vacuum (that apparently can produce anything) always existed, it would have created our universe an infinite time ago and infinite amount of times exactly as it is now. In addition, there would be an infinite amount of universes that ALSO existed that I typed this sentence without punctuation. You have just traded one brute fact (our universe) with an infinitely more complex brute fact (a truly infinite amount of universes). I think William of Occam would have something to say about that. 

What keeps the quantum vacuum from popping out universes? I would be thoroughly impresses if it popped out a can of Coke. Speaking of cans, all you have done it kicked the can back (see next section).

It relates to your argument(s), because it totally removes any agency from the cause of the Universe. It's just random.
Like your first cause, god, needs to be a brute fact to you... I keep things simple and think it's more reasonable to consider spacetime as the brute fact.

If you posit a physical thing always existing, you have to wave your hand at the impossible logic of traversing an infinite series of events and just declare it must be so for the sole reason of avoiding a first cause. Fine. You are probably willing to pay that intellectual price and go with 'brute fact'.

However, God is by definition not a brute fact. It is not that he does not have an explanation, it is that the explanation of his existence is built into the definition of God. Plain and simple, if God exists, he is a necessary being. That means he does not need an explanation. 

Spacetime has the added benefit of having actually been verified to produce these particles... which should be a very good hint.

First, quantum vacuum =/= spacetime. 

Second, the energy for the particles are already in the quantum vacuum. We don't understand is what determines when they will materialize and fade back into the energy field. You have an extraordinary leap to get from indeterminately appearing particles from an energy field that produces, well, indeterminately appearing particles to a can of Coke appearing, let alone producing a universe with its own matter, energy, physical laws, etc.  

After all this, believing in God seems pretty mundane.

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Not with real objects (1). Premise 2 still intact.

It's questionable whether past events are real objects...they did exist but they don't exist now.

You are equivocating between the 'past' and physical events that were in the past. Of course they are real. We would not have the effect today without the causes of yesterday.