In early January of this year if you go back through Blogging the Boys the general thought was McCarthy was definitely leaning towards calling his own plays, although it was not written in stone. He had remarked that the only time he gave up play calling at Green Bay was for a limited time and that it was a mistake. He took the play calling back. The following season McCarthy told Tom Pelissero he would "never give up play calling again".
He told 105.3 that he "loved play calling".
In Late December in his interview with Peter King, he told King that "the play caller on Sunday should be the same person who installed the offense on Wed, Thurs, and Fri", leaving the impression he would be strongly involved in that process, but again, no promises.
As far as I can tell, it was reported on Jan 16 that Moore would be calling plays. Prior to that, there was talk that Moore had been offered a job as OC for the University of Washington. I don't know the timing or details of all that or how it fit into the situation with McCarthy.
I can find no "direct quote from McCarthy" himself as you requested.
Based on the interviews and the context of his various statements, I drew the same impression that so many were reporting, that he would most likely be calling plays, but again it was not written in stone.
I still believe that was MM's preference, but who knows what all factors entered into the situation leading to the final decision.