I think you are just trying to restate what Mycroft has said, but I don't understand why some of these conclusions have to be made. For example why couldn't the whole of a finite reality be suspended in nothingness? What property does reality have that requires it to be suspended in something?
If reality has finite dimensions then why must the frame of reality have a creator? Couldn't the frame of a finite reality be part of God? Assuming we believe there was something "before" the Big Bang then why must we apply time to this reality? The space-time continuum is contained within the known universe. Anything outside this universe (or "before" if you will) would not necessarily be subject to time.
Also when discussing infinity it is common to imagine this applying to spacial dimensions, but why must everything be infinite? If all of reality had no spatial boundaries then couldn't it still contain finite energy? If God is infinite, but not all encompassing, then couldn't he create our finite universe and decide not to be part of it?
I suppose my overall point is that there seems to be a lot of assumptions made that don't really need to be made. It is possible to chose one set of assumptions and say, "Ok these assumptions are illogical when put together. A God like this cannot exist." However it is very easy to change the assumptions. There is so much we don't know about God (or the whole or reality) that it is easy to imagine God having many different properties. It seems absurd to insist on one set of assumptions for what exists outside the Big Bang when we really don't know anything about it.