Getting one post from multiple categories

cat_posts.php

<?php
function query_features() {

    global $query;

    // Setup arguments for our query
    $agencies = array(
      'extension' => 'AgriLife Extension',
      'research'  => 'AgriLife Research',
      'college'   => 'College of Agriculture &amp; Life Sciences',
      'tfs'       => 'Texas Forest Service',
      'tvmdl'     => 'TVMDL'
    );

    // Get the category ids from slugs
    $cat_ids = $this->get_cat_id( $agencies );

    $cat_args = array(
      'include' => $cat_ids,
      'orderby' => 'name',
      'order'   => 'ASC'
    );

    $categories = get_categories( $cat_args );

    $slides = array();

    foreach( $categories as $cat ) {
      $args = array(
        'showposts'         => 1,
        'category__in'      => $cat->term_id,
        'caller_get_posts'  => 1
      );
      
      $post = get_posts( $args );


        setup_postdata( $post );

        $slides[] = array(
          'img'     	=> $this->get_thumb( $post[0]->ID ),
          'caption' 	=> $this->get_title( $post[0]->post_title ),
          'permalink'	=> get_permalink($post[0]->ID),
          'pubdate'   => get_the_time( 'U', $post[0]->ID)
        );

    }

    // Sort the slides array by 'pubdate' descending
    usort($slides, array( $this, 'cmp' ) );

    return $slides;

  }