All you don't really need in WP. Please disable carefully!

wordpress_dontneeds.php

<?PHP

//note: you should use these hook in functions.php file and / or (mu)plugin

//disable WordPress emoji
remove_action( 'wp_head', 'print_emoji_detection_script', 7 );
remove_action( 'wp_print_styles', 'print_emoji_styles' );

//disable Gravatars support
function __default_local_avatar()
{
    // this assumes default_avatar.png is in wp-content/themes/active-theme/images
    return get_bloginfo('template_directory') . '/images/default_avatar.png';
}
add_filter( 'pre_option_avatar_default', '__default_local_avatar' );

//to be continued...
?>