[[That seems to imply that not only is creation of self-replicating molecules by naturalistic means impossible, but so is the actual replication process once they do exist.]]
Not really, because once created fully functional, it has all the ‘mega-informaiton’ in it’s purest form fro mwhich to draw on for replication- As species don’t need to ‘evolve higher’, they are thus not hampered by the impossibilities that face naturalism- and can and do go from completed to less fully functional via adaptions and mutaitons- which is exactly what we see in nature and the evidneces- going from pure to less pure as entropy results (Which perfectly follows the second law btw)
The requirements of this irreducible complexity thoery seem to be that any change in the form will render the organism unsurvivable. That would apply to de-evolution as well as evolution. Every species is already "irreducibly complex" as it exists.