First post outside of loop, homepage only?

Question

Because of the way my templates are structured, I need to pull the first/sticky post from the site outside of the standard loop, just on the homepage. I'm using _s (underscores.me) as a base, so the current loop on the index look like this:

    <?php if ( have_posts() ) : ?>

  <?php /* Start the Loop */ ?>
  <?php while ( have_posts() ) : the_post(); ?>

    <?php
      /* Include the Post-Format-specific template for the content.
       * If you want to overload this in a child theme then include a file
       * called content-___.php (where ___ is the Post Format name) and that will be used instead.
       */
      get_template_part( 'content', get_post_format() );
    ?>

  <?php endwhile; ?>

<?php elseif ( current_user_can( 'edit_posts' ) ) : ?>

  <?php get_template_part( 'no-results', 'index' ); ?>

<?php endif; ?>

What do I have to do to query the first post (I'd like to use the same get_template_part construct if possible), on the homepage only, and not have it interfere with counts for paging past the homepage?

Thanks,

UPDATE

Next part of the question; I now want to add a custom query inbetween the separated first post, and the continuation below, that only pulls a few posts in from specific categories. My query doesn't seem to do anything - what's wrong with it? Are those two main loops interferring with it somehow?

    <?php
$args = array(
    'cat' => 6521,//(int) - use category id.
    'category_name' => 'featured', 'dossier', 'destacado',
);    
$featured_posts = new WP_Query( $args );

// The Loop
if ( $featured_posts->have_posts() ) :

while ( $featured_posts->have_posts() ) : $featured_posts->the_post();
  echo '<div style="background-color:#f00;">';
  the_title();
  echo '</div>';
endwhile;

endif;

// Reset Post Data
wp_reset_postdata();
?>

Thanks,

Answer 1

try and add this before your code:

<?php if ( have_posts() && is_home() && !is_paged() ) : ?>
    <?php the_post(); ?>
    <?php get_template_part( 'content', get_post_format() ); ?>
<?php endif; ?>

Answer 2

If I understand correctly you want to fetch the first post using a separate query, perhaps in order to distinguish it from the rest of the posts in your markup. To accomplish that, I'd try something like this:

<?php global $paged;
<?php if (is_home() && !$paged) : ?>

  <?php
  $posts_per_page = get_option('posts_per_page');
  $num_featured_posts = 1;

  query_posts(array('posts_per_page' => $num_featured_posts)); ?>

  <div id="featured">

    <?php if ( have_posts() ) : ?>

      <?php while ( have_posts() ) : the_post(); ?>

        <?php get_template_part( 'content', get_post_format() ); ?>

      <?php endwhile; ?>

    <?php elseif ( current_user_can( 'edit_posts' ) ) : ?>

      <?php get_template_part( 'no-results', 'index' ); ?>

    <?php endif; ?>

  </div>

  <?php
    wp_reset_query();
    query_posts(array('posts_per_page' => $posts_per_page - $num_featured_posts, 'offset' => $num_featured_posts));
  ?>

<?php endif; ?>

<div id="posts">

  <?php if ( have_posts() ) : ?>

    <?php while ( have_posts() ) : the_post(); ?>

      <?php get_template_part( 'content', get_post_format() ); ?>

    <?php endwhile; ?>

  <?php elseif ( current_user_can( 'edit_posts' ) ) : ?>

    <?php get_template_part( 'no-results', 'index' ); ?>

  <?php endif; ?>

</div>

Regarding your update

I think you have an error in your query. First of all, you are using both cat and category_name which do the same thing using different parameters (id vs. slug). This is probably not much of an issue though, since one will probably take precedence.

I think the issue is that you are passing multiple slugs as the category_name parameter, while it takes only one. Instead, use category__in and pass category IDs in an array like so:

$args = array(
   'category__in' => array(1, 2, 3)
);

Also, when you are having issues with WP_Query it might be a good idea to add wp_reset_query() calls before and after your query to make sure it's not interfering with surrounding queries, add in some of the most common query variables like post_type, posts_per_page, paged etc. to make sure they are not being overridden elsewhere. Lastly, sometimes just printing the query object using print_r($featured_posts); will give you valuable debugging information.