There isn’t any way to do that with WP_Query directly. This would take a more complex query then WP_Query is capable of.
To be honest, I’m not even sure I help with the query you’d need because wp_posts is contected to wp_terms thought both wp_term_relationships and wp_term_taxonomy.
A very simplified form or the WHERE would be
WHERE (post_type = 'post' AND
term_id = 304) // this is completely wrong
OR (post_type IN(your other post types))
