For the second part, you're assuming that they just didn't offer enough money. It's very likely instead that SJ didn't want to associate her brand with this business.
It's quite likely that SJ would suffer from severe reputational damage from being the literal voice of AI.
The sky voice has been part of the app since the launch, it was not newly launched for GPT4o.
You're missing a key step in your logic chain: That they pulled the voice when SJ made a public complaint does not imply that they thought it was a soundalike, or that they documented they were making a soundalike, or that a soundalike is wrong, or that they thought they were doing something wrong when they hired the Sky voice actor. It just means that they pulled the Sky voice on public request from SJ.
That, combined with SJ reports that she turned down a licensing deal, and WaPo reporting that the Sky voice actor sounds like the voice delivered in ChatGPT, are pretty much the only facts we have right now.
As to SJ brand decisions -- maybe. I would bet the offer was low / not discussed, instead of it being substantial. But, that is also speculation.