But it’s a small number of voices who all sound distinct. So it seems unlikely they wanted to released two similar voices in that context. Especially when it specifically sounds like the voice actor in a film as an AI.
If they had released the voice they could have argued they wanted something different, but by waiting and going with Sky after the negotiations failed it’s a different matter.
they tried to get Scarlet to do the voice and after she declined OpenAI found someone
This is exactly the question the Washington Post set out to answer, and the answer is "no": that didn't happen.
Simply recording Sky’s voice beforehand doesn’t imply a different intent. This isn’t animation where you’re trying to match two mediums and you want the actors recording first. Having a similar voice to work with would have been useful internally to know if they wanted to pay what it might cost to use her voice.