Magento 2 – How to Add Custom Tab in Product Page

Please only ask one question at once. Anyway, here you go:

1. The following content for the local.xml works. It will add a new tab on the product page. If it does not work, your layout XML file is probably not loaded correctly.

   <?xml version="1.0"?>
   <layout version="0.1.0">
       <catalog_product_view>
           <reference name="product.info">
               <block type="catalog/product_view_attributes" name="features_product_tab" as="features_tab" template="catalog/product/view/features.phtml">
                   <action method="addToParentGroup"><group>detailed_info</group></action>
                   <action method="setTitle" translate="value"><value>Features</value></action>
               </block>
           </reference>
       </catalog_product_view>
   </layout>
   

2. This is not possible in a nice way. But you could write something unique into the static block to mark it empty and then change the way Magento renders the tabs in order to hide "empty" tabs. Therefore, write e.g. EMPTY into the static block you do not want to be rendered. Magento will automatically add a paragraph tag around it, so it becomes <p>EMPTY</p>. Then, in your catalog/product/view.phtml change the tab rendering like that:

   <div class="product-collateral toggle-content tabs">
       <?php if ($detailedInfoGroup = $this->getChildGroup('detailed_info', 'getChildHtml')):?>
           <dl id="collateral-tabs" class="collateral-tabs">
               <?php foreach ($detailedInfoGroup as $alias => $html):?>
                   <?php if ($html != '<p>EMPTY</p>'): ?>
                       <dt class="tab"><span><?php echo $this->escapeHtml($this->getChildData($alias, 'title')) ?></span></dt>
                       <dd class="tab-container">
                           <div class="tab-content"><?php echo $html ?></div>
                       </dd>
                   <?php endif; ?>
               <?php endforeach;?>
           </dl>
       <?php endif; ?>
   </div>
   

You need to add this in the layout xml file from one of your modules (or local.xml of your theme).

<catalog_product_view>
    <reference name="product_info">
        <block type="your_block/alias_here" name="some_name_here" as="some_alias_here" template="path/to/template.phtml">
            <action method="addToParentGroup"><group>detailed_info</group></action>
            <action method="setTitle" translate="value"><value>Tab Title Here</value></action>
        </block> 
    </reference>
</catalog_product_view>

Then create your block and the template with the content you need.