Ajax navigation and scripts loaded only on certain pages

If the plugins are nice about it and register all of their scripts upfront, and then just enqueue them as needed, you should be able to enqueue all of them to load all the time. Find out the handles they were registered with and enqueue them.

add_action('wp_enqueue_script', function() {
    wp_enqueue_script('example-handle');
    wp_enqueue_script('another-example-handle');
}, 20);

However, some plugins register scripts through the wp_enqueue_script() function even when they conditionally load them. For those, you will need to copy those enqueue statements and modify the paths to the scripts so that they’ll load correctly.

add_action('wp_enqueue_script', function() {
    $url = plugins_url('js/example.js', 'example-plugin/x');
    wp_enqueue_script('example-handle', $url /* and any other params they had */);
}, 20);