With respect, 100% speculation, unless you have a jot of evidence otherwise.
I tend to look at the absence of activity of activity of OG going through the T9 in the media to suggest that there was no combing over the T9.
Of course, if you can point me at such reports, I will be grateful to thank you for your enlightenment, and be pleased to agree the step prior to the remit was to check out the T9 and rule them out.
Is there anything whatsoever to show the McCanns were investigated by OG before the remit? Or the remainder of the T9?
It is how it is done.
The object of reopening a cold case is to find out what happened.
Irrespective of who has carried out initial investigations it is inevitable that fresh eyes will often pick up on something which has been overlooked.
It may be a game changer or it may be trivial and lead nowhere ... but it is added to the sum of knowledge.
To do that requires to go back to the very beginning of the case and interview yet again those at the heart of it ... it involves ploughing through every existing scrap of paper ... only once that has been dealt with and eliminated is it possible to either recommend no change or to recommend progressing to the next stage.
Which may include interviewing new suspects or persons of interest.
In initial leaks the names of those going through this process of elimination in Portugal were put into the public domain. Prior to that the Oporto team and the London team separately went about their business with discretion.
I fail to see why the logic of the situation defeats you.
Why would Scotland Yard fail to take procedural steps right at the beginning of a review which would save them the risk of egg all over their faces at a later date? Failure to do so would be an unprofessional course of action ... not to mention very sloppy police work.