Hello,
you can use the following code inside your functions.php
add_action( 'geodir_add_listing_page_title', 'geodir_add_listing_page_title_custom',10 );
function geodir_add_listing_page_title_custom()
{
global $wp, $term, $post, $current_term, $wp_query; $gd_post_type = geodir_get_current_posttype();
$post_type_info = get_post_type_object( $gd_post_type );
echo "List ".$post_type_info->labels->name;
}
note the
echo "List ".$post_type_info->labels->name;
after the echo you can insert your own text, e.g.
echo "This is my custom text";
If you want to use the name of the current post type you can use
$post_type_info->labels->name
About your other questions, you can translate/rephrase the strings, using the .po file inside the language folder, more info here
http://docs.wpgeodirectory.com/translate-core/