How do I render a field twice with two different field formatters?
So in drupal 7 you could use:

$output = field_view_field('node', $node, 'field_foo', array('type' =&gt; 'some_formatter', 'settings' =&gt; array(...), $langcode));


to render a field with a specific formatter. The drupal 8 the equivalent is: 

$output = $node-&gt;field_foo-&gt;view(array('type' =&gt; 'some_formatter', 'settings' =&gt; array(...)));


source: Change record

Now to render the fields I would create a preprocess for a node

function HOOK_preprocess_node(&amp;$variables) {
  $variables['my_field_formatter1'] = $node-&gt;field_foo-&gt;view(array('type' =&gt; 'some_formatter', 'settings' =&gt; array(...)));
  $variables['my_field_formatter2'] = $node-&gt;field_foo-&gt;view(array('type' =&gt; 'some_formatter', 'settings' =&gt; array(...)));
}


and then print my_field_formatter1 and my_field_formatter2 in your twig template for the node.