Add order / customer data on License Key response.

plugin.php

<?php
/*
Plugin Name: Customizations
Description: Customizations made to plugins or theme using Wordpress hooks.
Version: 9000
*/

// -----------------------------------------------
// ADD CUSTOMER & ORDER INFORMATION TO RESPONSE
// -----------------------------------------------

// @hooked to
add_filter( 'woocommerce_license_keys_activate_success_response', 'response_with_customer_order_data', 10, 2 );
add_filter( 'woocommerce_license_keys_validate_success_response', 'response_with_customer_order_data', 10, 2 );

/**
 * Returns the response with additional customer / order data.
 *
 * @link https://docs.woocommerce.com/wc-apidocs/class-WC_Order.html
 *
 * @param object $response
 * @param array  $request
 *
 * @return object $response should be returned back.
 */
function response_with_customer_order_data( $response, $request ) {
    
    // Get woocommerce order
    $order = wc_get_order( $request['license_key']->order_id );
    
    // Get customer information
    $response->data['customer'] = [
        'id'        => $order->get_customer_id(),
        'email'     => $order->get_billing_email(),
        'firstname' => $order->get_billing_first_name(),
        'lastname'  => $order->get_billing_last_name(),
    ];
    
    return $response;
}