Disable Or Redirect WP-login.php

Try this in your theme's functions.php
========================================

1.-------------------------------
add_action('init','custom_login');
function custom_login(){
 global $pagenow;
 if( 'wp-login.php' == $pagenow ) {
  wp_redirect('http://yoursite.com/');
  exit();
 }
}

2. ---------------------------------
// Hook the appropriate WordPress action
add_action('init', 'prevent_wp_login');

function prevent_wp_login() {
    // WP tracks the current page - global the variable to access it
    global $pagenow;
    // Check if a $_GET['action'] is set, and if so, load it into $action variable
    $action = (isset($_GET['action'])) ? $_GET['action'] : '';
    // Check if we're on the login page, and ensure the action is not 'logout'
    if( $pagenow == 'wp-login.php' && ( ! $action || ( $action && ! in_array($action, array('logout', 'lostpassword', 'rp'))))) {
        // Load the home page url
        $page = get_bloginfo('url');
        // Redirect to the home page
        wp_redirect($page);
        // Stop execution to prevent the page loading for any reason
        exit();
    }
}

3. ---------------------------
function custom_login_page() {
 $new_login_page_url = home_url( '/login/' ); // new login page
 global $pagenow;
 if( $pagenow == "wp-login.php" && $_SERVER['REQUEST_METHOD'] == 'GET') {
    wp_redirect($new_login_page_url);
    exit;
 }
}

if(!is_user_logged_in()){
 add_action('init','custom_login_page');
}
This code snippet will:

Redirect all website visitors to new login page.
Logout will work without any problem
On your custom login page you will have to create custom login , registration and password reset forms, However your custom forms can safely post data to wp-login.php as post requests are not redirected.