Adding Auto-suggest capability with the Question-tags field on ask-a-question page

You can open the question-submit-form.php file and find the line 58 to 60 then replace it with the following code: 

<label for="question-tag"><?php _e( 'Tag', 'dwqa' ) ?></label>
      <?php
          $exclude_tags = get_term_by( 'name', 'FAQ', 'dwqa-question_tag' );
          $exclude_tags_id = array();
          if( ! empty($exclude_tags) ) {
              $exclude_tags_id[] = $exclude_tags->term_id;
          }

          wp_dropdown_categories( array(
              'name'          => 'question-tag',
              'id'            => 'question-tag',
              'taxonomy'      => 'dwqa-question_tag',
              'hide_empty'    => 0,
        'selected'      => isset( $_POST['question-tag'] ) ? esc_attr( $_POST['question-tag'] ) : false,  
               'quicktags'     => array( 'buttons' => 'strong,em,link,block,del,ins,img,ul,ol,li,code,spell,close' ),                 'class'         => 'input-block-level',
               'exclude'       => $exclude_tags_id
           ) );
     ?>

Thanks, Dominic! 
This is great. We are looking to improve this as well. 
Please see the image below for end-functionality we are trying to achieve.

 

Here is another scenario :
 
 
 

And here is another scenario. This is the functionality we are trying to achieve. Can you help me?