Interesting idea. I don't think it is a new argument as I would argue it heavily resembles the Cosmological Argument. In turn, I do not think you have answered the concerns of the critics.

Let us first examine your first premise. The argument rests on everything needing a cause. What caused God? Some argue God does not need a cause because God is God. I consider this a cheap shot, but due as you may. Just note that this smashes your own sequencing later in the post:

since things can't be descended from no initial explanation.

Next, your second premise. Regarding Occam's razor, it takes in simplest of a "set" of arguments. Note this is "good" explanations or "proper" explanations. However, to say all things could descend from a single explanation is to say a single explanation is a proper element of the set. This leads back to your first premise, which again is not truly justified. By assuming a single explanation is a proper element of the set is essentially assuming God’s existence in and of itself.

This might be confusing, so I will try to give another example of what I mean by “proper” and “set”. Let us try to examine the explanation for “why I need coffee in the morning”. [1] I feel tired in the morning and coffee wakes me up. I need to feel awake so I can get to work. This is a proper element. [2] I enjoy the taste of coffee, so when I drink coffee I am happier. When I am happier, I am more productive. Because I am more productive, I can get more done at work. This is also a proper element. [3] I fill my bottle with water because it is more accessible. This is not a proper element because it is not a proper explanation for “why I need coffee in the morning”. In fact, it says nothing about coffee or why I need it. So using Occam’s razor, we would consider [1] and [2] and not [3] ever. However, because we take up the simplest explanation, we choose [1] and our explanation.

The coffee example was easy to understand. However, when we apply this to “why the universe exists”, it becomes more complicated. You are simply assuming “single explanations” is a proper element of the set based off of your premise 1.

Your premise 3 is not sound to me. Note the Big Bang Cosmology. I actually believe it is vice-versa. If something had a mind, why did it choose to start causing then and there. As to why a natural event didn't do it earlier? Because there was no earlier. In a natural explanation, time and space did not exist before everything started. However, by saying something that had a mind started everything, then this object with a mind would exist. What capacity does this entity exist in if nothing existed?