I thoroughly enjoyed reading how you came to conclude the word "nonexistence" has the same problems I did, it simply is a concept you can't talk about, and you can't find! Hence, the idea that anywhere you look you find existence, and if you had the power of infinite travel you would still perpetually find existence hence the comment "in all directions." But the part it seems most people here struggle to grasp is the argument isn't purely physical, it is meant to be a metaphysical argument. It is OK for the universe to be finite as long as there is a greater existence within which it dwells and permeates it. For example, there is an entire world of ideas which dwell in our minds, their existence exists within the existence of our bodies. Thus, you could say existence is tiered. Ideas exist within our bodies, our bodies exist within space-time, and space-time exists within ??? (possibly God? this is where the metaphysical argument comes in).
Now, I also agree with you I could better explain how I gain the omni's from all this.
We start with the Eternal component--all time--and work our way from there. You can't say "there was a time when there was nothing." That, simply, wasn't a time. That was nothing, so we can ignore it (humor intended).
i) Omnipresence is infinite presence in all directions. So, one existence without divide that is everywhere.
n. This, alone, doesn't solve the need for infinite existence because "presence" alone isn't a thing, and isn't an existence. It needs to be able to "do" something. "Doing nothing" for an eternity is--begging the question here--pure nothingness. Hence we add in infinite potential and awareness.
ii)Omniscience is infinite awareness in all directions. So, one awareness without divide that is everywhere.
n1. I am purposely defining omniscience using different words than are typical because "knowledge" is a finite word, and adding the word "all" before it doesn't necessarily correct this limitation. The word "aware" is very open-ended and can't be put in a box, so-to-speak.
n2. Omnipresence and omniscience aren't enough to create change, so nothing changes here--we still have infinite nothingness.
iii)Omnipotence--now we add in potential in all directions
n. combined with omnipresence and omniscience change can occur anywhere, in all directions, infinitely. But, even with potential, there still is no "need" for it to occur. My car with a full tank of gas can sit perfectly still in the same spot for a very long time and go nowhere, even with perfect potential to do so. This is where we need the sort of "key and ignition" so-to-speak of this whole machine of existence.
iv)Omnificence--unlimited creativity
n. this concept is reliant upon everything else above, and to say it ever "stops" would be to put a limit on it so it wouldn't be "unlimited" creativity. Thus, this is what keeps the machine of "change" going ad-infinitum. This, ultimately, perpetuates existence and makes it eternal thus it truly goes full-circle from here.