I think I understand your points Fresco but the 4 points I made were strictly based on objective reasoning. If you are interested in a discussion, then my objections to you are as follows:
1. Regarding your first point, you do not say anything about reality and as I am only focused on what is real, I won't address it.
2. I strongly disagree with your second point. How could you hypothetically respond to the following: "If there is an existence, then there is at least one thing that is truly real; therefore something is indubitably real." How could you rationally fault this? It's as impossible as rejecting existence.
3. Let's temporarily forget the pre-fix "omni". One thing encompasses all things. Naturalists believe this to be substance or matter. Therefore substance or matter is in everything. To be in everything is equivalent to being omnipresent. Omnipresent is just a short way of putting it.
Aside from omnipresence, the only other two traits that cannot be copied or simulated, are omnipotence and omniscience. Given this, we are rationally obliged to acknowledge them as indubitably real as they cannot be copied or simulated.
What I mean by this is that we can't just acknowledge omnipresence and then ignore omnipotence and omniscience. That's being biased and not true to reason and the demands of doubt (an important aspect of reason that exposes truth).
4. Rationally establishing something as indubitably real is different to just arbitrarily attributing realness to something. Only the the aforementioned traits can't be copied or simulated. If something can be hypothetically simulated or copied, then you don't know if its the real thing (paintings and dreams are examples) but if something cannot be copied or simulated, then you know it is the real thing.