WordPress stores callbacks in an array keyed by hook name and then by priority. remove_action() looks in exactly one of those priority buckets — the one you name,…
A second WP_Query in a template is harmless right up to the point where you call the_post() on it. That method assigns the global $post and runs setup_postdata(),…
On every request WordPress fetches all options with autoload set to yes in one query, unserialises the lot and holds it as a single alloptions entry. That is…