Displaying co-authors outside loop

Hello – I’m trying to figure out how to get co-author information outside the loop. We have an admin who receives new stories daily from various site authors, and he handles creating new posts using their content and assigns them as the authors afterward.

Co-Authors Plus works great inside the loop. I can pull multiple authors into single posts with regular functions. But when I try using this outside of the loop, the admin name is pulled instead of the assigned author and co-author. The admin name is pulled when I use the_author() too, so this is consistent. In order to add the proper author name, I wrote this:

<?php echo get_the_author_meta('user_firstname',$id->post_author).' '.get_the_author_meta('user_lastname',$id->post_author); ?>

What’s would be the best way to pull multiple author names given the methods above, and/or is there a better way to do what I’m doing?