I contacted Oxford University Press to find out any additional information about the upcoming The Catholic Study Bible update. Below is their response:
"The publication date for the NABRE revised is early August.
It includes updates taking into account recent archaeological and textual discoveries
It has a complete revision of the Psalter
It has study notes, expanded essays and informational sidebars
It does have a Concordance"
Didn't exactly answer all my questions, like whether or not the essays and reading guide were updated since the second edition, but at least there is confirmation of a new publication date.