More fiddling with embedded posts, this time making changes to the code outlined in Embed Customisation Supporting “Co-Authors Plus” in order to make every authors name into a link to their post archive page.
/**
* Removes the title (David Stockdale).
*/
add_filter('embed_site_title_html','__return_false');
/**
* Adds the author's names (David Stockdale).
*/
add_action( 'embed_content', 'embed_author' );
/**
* Adds the author div to the embed iframe (David Stockdale).
*/
function embed_author() {
$output = '<div class="wp-embed-author"><ul>';
$coauthors = get_coauthors();
foreach( $coauthors as $coauthor ):
$output .= '<li>';
$authorArchiveLink = get_author_posts_url($coauthor->ID);
$output .= "<a href=$authorArchiveLink> $coauthor->user_firstname $coauthor->user_lastname</a>";
$output .= " ";
$output .= get_avatar( get_userdata( $coauthor->ID ), 20 );
$output .= '</li>';
endforeach;
$output .= '</ul></div>';
echo $output;
}