承認前はコメント投稿本人にも表示しない

wp-includes/comment-functions.php

comments_template関数の定義内にある

if ( empty($comment_author) ) {
$comments = $wpdb->get_results("SELECT * FROM $wpdb->comments WHERE comment_post_ID = '$post->ID' AND comment_approved = '1' ORDER BY comment_date");
} else {
$author_db = $wpdb->escape($comment_author);
$email_db = $wpdb->escape($comment_author_email);
$comments = $wpdb->get_results("SELECT * FROM $wpdb->comments WHERE comment_post_ID = '$post->ID' AND ( comment_approved = '1' OR ( comment_author = '$author_db' AND comment_author_email = '$email_db' AND comment_approved = '0' ) ) ORDER BY comment_date");
}

を、

// if ( empty($comment_author) ) {
$comments = $wpdb->get_results("SELECT * FROM $wpdb->comments WHERE comment_post_ID = '$post->ID' AND comment_approved = '1' ORDER BY comment_date");
/* } else {
$author_db = $wpdb->escape($comment_author);
$email_db = $wpdb->escape($comment_author_email);
$comments = $wpdb->get_results("SELECT * FROM $wpdb->comments WHERE comment_post_ID = '$post->ID' AND ( comment_approved = '1' OR ( comment_author = '$author_db' AND comment_author_email = '$email_db' AND comment_approved = '0' ) ) ORDER BY comment_date");
}
*/

とコメントアウト。