How can I make the email subject line be the name of the WordPress Post I am converting to PDF?
Is this available in the admin config section or can the PHP be hacked?
Is it also possible to make the PDF name the name of the post, as opposed to the home page name?
I think this is currently not possible. The main intent of the email function is to the to send the email to the user who want the article. It's not intended to send the email to an other person.
One problem is that the sender of the mail is still the PDF24 converter system and people don't have a chance to answer you, if you sent the document to him.
He can't see the real sender of the email and that the point why mails should only be sent to your private email address.