WP_Query in Genesis Child Theme

Hi all,

I want to use wp_query on my site homepage but outside and independent of the main post loop. The site uses a child theme based on the genesis framework.

Where exactly is the main query that supplies the posts for the main loop called? If I use an additional wp_query call on the main page that contains the loop do I need to do anything special to prevent the query I run from interfering with the query for the main post loop?

I would like to query for the single latest post in a particular category – what parameter do I need to pass to the query in order for it to return just one post?

If I wish to display the thumbnail (featured) image of this post how do I do it efficiently – should I modify the query itself or simply access the featured post based on post data returned by a simpler query.

Many thanks for any insights provided.