Many coronaviruses have furin-cleavage sites. MERS is one such coronavirus and that arose naturally. A furin-cleavage site in SARS-COV-2 is unique to the sarbecovirus lineage, but as this paper illustrates it is possible for it to acquire it naturally:
https://www.nature.com/articles/s42003-022-03421-w
We don't actually know most of the coronaviruses in the wild. And the closest known relative to SARS-COV-2 is quite evolutionarily distant, so there are a lot of potential unknown related coronaviruses that could have picked up a furin-cleavage site.
The arginine codon CGG is not necessarily a "human" codon. It can be found in other animal viruses as well. Proponents of a natural zoonotic spillover believe an intermediate host was involved, which could explain the presence of the double CGG codons. As well CGG codons are present in higher rates in SARS (natural origin) compared to SARS-COV-2 despite being relatively rare.
The Receptor-Binding Domain of the SARS-COV-2 spike protein also is similar to the RBD in its closest known relative BANAL-236 found in Laos.
SARS-COV-2 wasn't well-adapted to humans when it first surfaced and underwent significant initial change. And in particular its furin-cleavage site wasn't as optimal as the furin-cleavage sites in other coronaviruses.
All this is to say these aren't the smoking guns for a lab leak that Robert Redfield is suggesting they are. It is disappointing the House COVID origins investigation is likely to not have any dissenting voices.