Vantage is really a rough theme for SEO. If you have a directory, you are trying to get links, but then Vantage points all of those links away. Plus, there is a ton of duplication.
To get rid of the archives indexing, add this gist to the wrapper.php file – somewhere betweenand
That’ll do what SEO Yoast can’t. I love SEO for WordPress, but it has no way of noindex nofollow on archive pages for Vantage.