Of course it would be subject to natural selection, that's why it wouldn't get off the ground. It's environment would be teeming with life that was already very well adapted to it. We don't know how life (more specifically replication with inheritance and variation) started but it was in a very different world to today, and one that wasn't filled with competition.
What are you actually proposing anyway? That god magicked life into existence and then waited 4 billion years for evolution to do the rest of the job? This seems like god of the gaps nonsense.
I'm afraid you still have to justify Dawkins assertion that we would never see abiogenesis because the products would be swiftly digested.
You then....if you are supporting that assertion need to justify why the process of its digestion could never be observed.
Next comes your explanation for why the new organisms are invariably unfit when that idea would exclude any new species from developing. This is the point where yours, Steves and Dawkins conjecture fails big time because what you are asserting is:
New species can emerge from the single tree of life.
New species can never emerge from a new tree of life
Suggesting a special reason for the success of the original tree of life.
What is this and how does it work?