Displaying "First initial of first name & last name" for my buying customers that gave a review for privacy purpose.

custom-woocommerce-review-author.php

<?php

add_filter( 'comment_author', 'custom_comment_author', 10, 2 );

function custom_comment_author( $author, $commentID ) {

    $comment 	= get_comment( $commentID );
    $user 	= get_user_by( 'email', $comment->comment_author_email );

    if( ! $user ) {
    	return $author;
    } else {
        $firstname = (string) get_user_meta( $user->id, 'first_name', true );
        $lastname = (string) get_user_meta( $user->id, 'last_name', true );

        if( empty( $firstname ) OR empty( $lastname ) ){
        	return $author;
        } else{
		return esc_attr( $firstname[0] . " ". $lastname );
        }
    }
}