Sorting custom post types in edit.php : Post disappear

The problem is 'meta_key' => 'large_feature', in your last function, here the “large_feature” is a taxonomy, not a “meta_key”. Infact there is no post in wordpress which has “large_feature” as a “meta_key”. That’s the reason wordpress didn’t display any posts.

About ordering by taxonomy terms, wordpress doesn’t allow that like this. You can however customize the SQL query directly using posts_orderby or such filters, see http://codex.wordpress.org/Class_Reference/WP_Query#Filters