Other than save_post any other actions on add / edit post screen?

you can use load-{page-hook}. It is called prior to the admin screen loading.

add_action( 'load-post-new.php', 'post_listing_page' );
function post_listing_page() {
    // 'add new' page, you may have to check post type..
}

• {page-hook} on the ‘add new’ page of any post type, it is post-new.php
• {page-hook} on the edit page of any post type, it is post.php