The Bangkok Post today published an article that gives more information on the structure that Thai Wings will have, describing it as a "Light Premium" airline such as Silk Air, and that it will share the TG code and participate in Royal Orchid Plus.

Airline firm on spreading Thai Wings

I found the Coke/Coke Zero analogy interesting, because it brings to mind some ads Coke ran a few years ago in the USA to introduce the new Coke Zero brand. The ads showed Coke marketers that wanted to sue Coke Zero because it tasted too much like the real Coke. They were asking lawyers about it, and these confused lawyers were telling them "You can't do that. You're the same company. You'd be suing yourselves!"