So they assumed that a certain number of proteins needed to be assembled. Presumably as the minimum requirement for a replicator capable of evolving. Did they justify that assumption ? Because I don't think that anyone now would say that they knew.
As for your point about the RNA world, I am afraid gaps in our ideas act against your argument. They indicate that we do not know enough to come up with a reliable probability calculation.
As for your claims about the Flood I would disagree. The main attempt to explain the fossil record is based on the assumption that eco-systems were caught entire and somehow happened to end up in an order that matches the fossil record. But there is no clear match with geological age (this is especially disturbing given the reliance on accelerated radioactive decay to explain radiometric dating - it places quite strict constraints on the order in which beds form - the relative timing has to be the same and you have to compress the scale by many orders of magnitude). There are serious problems with the fossils actually found - I raised some on marine fossils in another thread, but there are others. Why for example do we find a sequence of whale ancestors leading TO modern whales instead of FROM modern whales ? Why don't we find whales swiming with icthyosaurs and plesiosaurs, before their shore dwelling and terrestrial ancestors, which by your scheme would be fossilised last ?
I would say that it is clear that the Flood here is "saved" by ad hoc assumptions which sound plausible (especially to believers) in the abstract but have not been detailed to the point where they can be tested, and that they some very hard work is needed before we can say that they even represent a viable alternative to the standard view within the restricted area of the fossil record. They have not been presented in a falsifiable form maing detailed predictions. The geological record as a whole contains many other features which seem to add up to a conclusive case that Flood geology cannot reasonably explain what we see.
If the Flood is hard to rule out it is no more than a verification of the Duhem-Quine thesis. ANY theory can be defended from falsification by making enough ad hoc assumptions. Science works because scientists give up defending theories which require that much work to keep viable.