Changing the header on post listing page in admin area

To insert links at that position, you need the filter views_edit-POST_TYPE, replacing POST_TYPE by the slug of your CPT.

Example:

add_filter( 'views_edit-portfolio', 'custom_list_link_wpse_79975' );

function custom_list_link_wpse_79975( $views ) 
{
    $views['dashboard'] = '<a href="' . admin_url('index.php') . '">Dashboard</a>';
    // $views['another-view'] = '<a href="#">Contact</a>';
    return $views;
}

Results in:
views edit cpt


The second question should have been a separate Q, but while we at it…

You could create your own meta box, but there’s a couple of useful hooks:

// Another possible action hook is: post_submitbox_start
add_action( 'post_submitbox_misc_actions', 'custom_publish_link_wpse_79975' );

function custom_publish_link_wpse_79975() 
{
    // check for post type
    global $current_screen;
    if( 'portfolio' != $current_screen->post_type )
        return;

    echo '<div class="misc-pub-section my-link">
        <a href="' . admin_url('edit.php?post_type=portfolio') . '">Cancel</a>
        </div>';
}

Which results in:

cancel in publish meta box