In all of this talk--much too much of it--a single meaningful question is embedded, and although not at all well phrased & quite ambiguous, part of it can be answered definitively:
"...So, how is it that the Pensacola convoy was directed to take the route through Torres Strait - from what we do know, not because of the attack on Pearl Harbor but because of a decision made sometime before the convoy departed from Hawaii?"
1) Yes, I believe the decision on routing predated the Pearl Harbor attacks.
2) Suggestions: Think Australia. Then think the NEI.