Because of cretins who insist on the opposite absurd "convention", the only way to insure that the actual meaning is conveyed is to use the words "Noon" for "12:00 AM" and "Midnight" for "12:00 PM".
Commas indicate a pause that would occur if the text were spoken out loud. Case in point:
Commas before and:   In a list of more than two items, use a comma before "and", unless the last two items in a list are more closely related to each other than they are to the other items in the list (in which case there would be no oral pause between the last two items).
The English language has no non-gender-specific pronouns.
We often use plural pronouns colloquially to refer to a single person when a gender- specific pronoun would be inappropriate or
irrelevant, and wish to avoid repeating the more stilted conventional double term.