I recently installed the Co-Authors Plus plugin into xLander, but saw that it only updates the additional author on the WP back-end, not on the front-end blog post itself. The documentation didn't make it very clear where or how I would go about changing the code/function to make the second author name appear. Please be sure to let me know if this is possible, and if so, how it would be done, and we can go from there. Thanks!
You'll need to add the plugin function in the theme. You can search in the theme files, for example, you can use notepad++, for the_author_posts_link and get_the_author functions and change like in their documentation: