Well-put, and in few words.
The USAFIA docs + Abe Silverman's Narrative (with Diary excerpts) + GEN Barnes' own report (written at the time) on the PENSACOLA Convoy's adventures all more or less confirm this, both in terms of general strategic "thinking" in a very confused period, and on more specific details.
But, of course Japanese raiders were not much of a threat--although they did possess a dedicated Sentai for that purpose--and the likelihood of additional heavy units being that far off the beaten path (for whatever reasons) was nil. And I do not recall that PENSACOLA was the lone escort at any time during this journey, was she?
Even with a bevy of DDs, a determined submarine could achieve results (SEAWOLF v. three CLs & 8 DDs at Christmas Island being a good early-war example) so that point is slightly moot.
From the 19th of December on, the convoy was rather heavily escorted, as we know.