Auto add content such as pages upon plugin activation?

You can add those without a button:

register_activation_hook( __FILE__, 'my_plugin_install_function');

function my_plugin_install_function()
  {
   //post status and options
    $post = array(
          'comment_status' => 'closed',
          'ping_status' =>  'closed' ,
          'post_author' => 1,
          'post_date' => date('Y-m-d H:i:s'),
          'post_name' => 'Checklists',
          'post_status' => 'publish' ,
          'post_title' => 'Checklists',
          'post_type' => 'page',
    );  
    //insert page and save the id
    $newvalue = wp_insert_post( $post, false );
    //save the id in the database
    update_option( 'hclpage', $newvalue );
  }

This function will run when the user installs the plugin. For super smart control you should check if that option already exists and if the id is not 0 (that means failure)