If anyone has a clue which files I need to edit to make this happen, that would help as well.
I’m seeing the parameters for orderby in /wp-show-posts.php although they look incomplete. Not an expert in PHP but I could probably figure this out if I had some clues for where to look.
Edit: If it’s easier, I’ll mention that I don’t need to edit the metabox for any of this. I just want all posts to also check for the custom field the_field('active') and use that as a sort parameter following the default parameter. If ‘active’ is found for a post, it should appear before any post without ‘active’.