How to maintain changes to comment-template.php

There’s a filter for that: get_comments_link. Refer to source: return apply_filters( ‘get_comments_link’, $comments_link, $post_id ); In an appropriate place (such as a site functionality Plugin), just add a filter via callback: function wpse123906_filter_comments_link( $comments_link, $post_id ) { // Return your custom link return get_permalink( $post_id ) . ‘#disqus_thread’; } add_filter( ‘get_comments_link’, ‘wpse123906_filter_comments_link’, 10, 2 );

How to edit label_submit styling?

You can target your submit button in css like this. This will look for a input element with type=”sunmit” in container id respond. So make sure your container id is respond otherwise change it too. #respond input[type=submit] { /* your styles */ }