I think at least one of those points is one of your tropes.
I don't see how a zombie has to be dualistic since they have no more about them than mechanism.
What Carroll is doing here is what Dennett does which is in effect saying we can only study mechanism therefore there is only mechanism.
Is Chalmers actually proposing dualism or is he being outed as a dualist. Is he proposing a soul thing or is he like Searle suggesting a mechanism which would remain hidden if Dennetts lazy and sloppy methodology prevail?
Not sure which point you mean as being one of 'my tropes', I quite often mention different axioms. is that it? If so it being a common point raised doesn't make it wrong and it's one that Carroll specifically raises.
I think we have to be careful here - Carroll's using dualist in a specific explained sense and rules out the Cartesian approach - it's covered in the first para. I disagree that Carroll is stating that there is only mechanism - rather he sees it as the simplest solution. This reads like your common conflation of methodological and philosophic naturalism in saying there doesn't seem to be a methodology to study non naturalist (and I am unsure that there is a sensible definition of the term) claims, does not mean that someone is stating there is no such thing.
Again I think we have to be careful that you seem to be using dualist in the Cartesian sense. it seems to me that both Chalmers and Searle are proposing a dualism in that the motivation for the actions of the zombie are not in the zombie itself, and the meaning of the signs in the Chinese Room are not determined by the 'worker' in the room. It's that the mechanism is separate rather than hidden that creates the dualism. I also don't see Carroll as here attempting to say that Chalmers is categorically wrong here but attempting to draw out the differences in approach. I think his use of the term 'poetic' is ill advised because of the connotations it creates.