Displaying the author of next and previous posts in pagination?

Yes, you can do that. Change <?php previous_post_link(); ?> and <?php next_post_link(); ?> with the following code:

For previous post:

  <?php
    $prev_post = get_previous_post();
    $prev_user = get_user_by( 'id', $prev_post->post_author );
    if (!empty( $prev_post )): ?>
      <a href="https://wordpress.stackexchange.com/questions/248618/<?php echo $prev_post->guid ?>"><?php echo $prev_post->post_title ?> (<?php echo $prev_user->first_name . ' ' . $prev_user->last_name; ?>)</a>
    <?php endif ?>

For next post:

  <?php
    $next_post = get_next_post();
    $next_user = get_user_by( 'id', $next_post->post_author );
    if (!empty( $prev_post )): ?>
      <a href="https://wordpress.stackexchange.com/questions/248618/<?php echo $next_post->guid ?>"><?php echo $next_post->post_title ?> (<?php echo $next_user->first_name . ' ' . $next_user->last_name; ?>)</a>
    <?php endif ?>

You also can control from which categories WordPress should select previous and next posts. get_previous_post and get_next_post accept two parameters:

• (bool) $in_same_cat — prev/next posts will be selected from the same category as you current post
• (string) $excluded_categories — posts related to these categories will be skipped

More details about these parameters you may find here