Showing comment form under each paragraph
I think you will need to do a couple of things. First is to create a comment form under each paragraph:

Drupal 7:

$comment = new stdClass;
$comment-&gt;nid = $nid;
$form = drupal_get_form('comment_form', $comment);

print render($form);


Then I would suggest using some jQuery to hide the forms, showing it only when the user clicks on the link. You can assign a unique class to the $form (see form API reference for more info) so that only the comment form for the specific paragraph shows, instead of all of them when any given link is clicked.