Imo your understanding is wrong. The inquiry is the investigation itself;
The “inquiry” (inquérito), led by a Public Prosecutor,is the stage that opens criminal proceedings with the purpose of investigating the possible perpetration of a crime, detecting its perpetrators and their responsibility and collecting evidence in view of a decision on whether there will be a formal charge or prosecution.
https://gddc.ministeriopublico.pt/pagina/notes-portuguese-legal-terms
It's you whose understanding is wrong.
You earlier wrote:
" I don't know what is meant by 'inquiry'. My best guess is that it refers to the inquiry stage of the process, which seems to follow the investigative stage".
And I replied to your post with the following@:
Perhaps inquiry means that stage in the investigation during which the arguidoship is conferred on a suspect so that they may be questioned?
As your quote above makes clear the inquiry is the investigation stage during which perpetrators are identified not as you had stated the stage AFTER an investigation.
so I think on balance it is you that is mistaken.
Why would a Portuguese defence lawyer be unable to understand the law change and if he had been wrong why has no one ever come forward in 15+ years to say he was mistaken or lying? Not even Amaral? Why, when CB was made arguido was this as a result of "strong indications of the practice of a crime", when such a claim was not made wrt to the McCanns or Murat?