...older bio of Maury here:

https://babel.hathitrust.org/cgi/pt?id=mdp.39015031479978&view=1up&seq=156

...with some interesting sections detailing Maury's shifting his loyalty from the Union to Virginia, or at least his biographers' interpretation of that shift.

My position has always been the 14th Amendment and its proscription against civil or military office. I agree a presidential pardon likely cannot obviate congressional action via the 14th. That Maury made no attempt to hold further office can be traced to his age alone, if nothing else. He was into his 7th decade after all.

The particular can of worms involving pardons is also covered here:

https://trace.tennessee.edu/cgi/viewcontent.cgi?referer=https://en.wikipedia.org/&httpsredir=1&article=5110&context=utk_graddiss

...although there's nothing specific about Maury. It did make an observation (page 53) I hadn't seen before I wrote the word 'rehabilitate' reinforcing my general--not legal--point while addressing your question; 'rehabilitation' appears to be considered either by pardon or by congressional act.

Personally, I find the entire question interesting. The guidance underlying the renaming appears rather straightforward and is notable for its brevity. Considering the standards--in this case, "any person who served voluntarily with the Confederate States of America..."--Maury arguably may be the least culpable of the group, at least based on first impressions. But, since the shoe fits....

RS