coming-soon.tpl.php

<div class="coming-soon">
  <h1><?php print $node->title; ?></h1>
  This is a coming soon review
</div>

main-page.tpl.php

<div class="review">
  <?php if ($is_coming_soon) ?>
    <?php print $coming_soon; ?>
  <?php endif; ?>
  <?php if ($is_module_review) ?>
    <?php print $module_review; ?>
  <?php endif; ?>
</div>

module-review.tpl.php

<div class="module-review">
  <h1><?php print $node->title; ?></h1>
  This is a module review
</div>

mymodule.php

<?php

function mymodule_theme {
  return array(
    'mymodule_main_page' => array(
      'arguments' => array(),
      'template' => 'templates/main-page',
    ),
    'mymodule_coming_soon' => array(
      'arguments' => array('node' => NULL),
      'template' => 'templates/coming-soon',
    ),
    'mymodule_module_review' => array(
      'arguments' => array('node' => NULL),
      'template' => 'templates/module-review',
    ),
  );
}

function mymodule_preprocess_node(&$variables) {
  $node = $variables['node'];

  if ($node->type == 'mymodule') {
    $variables['is_coming_soon'] = $is_coming_soon;
    $variables['is_module_review'] = $is_module_review;

    switch ($variables['view_mode']) {
      case 'full':
        if ($is_coming_soon) {
          $variables['coming_soon'] = theme('mymodule_coming_soon', array('node' => $node));
        } else if ($is_module_review) {
          $variables['module_review'] = theme('mymodule_module_review', array('node' => $node));
        }
        break;
    }
  }
}