Pre-populate Slug / Permalink with URL

I would like to not only pre-populate the title, tags, and categories, but would also like to pre-populate the slug / permalink as well.

Can I do this and if so how?

Here’s my functions.php code:

add_action( 'load-post-new.php', 'myplugin_post_new' );
function myplugin_post_new(){
    add_action( 'wp_insert_post', 'myplugin_wp_insert_post_default' );
}
function myplugin_wp_insert_post_default( $post_id ){
    wp_set_post_tags( $post_id, $_REQUEST['tags']);
    wp_set_post_categories( $post_id, $_REQUEST['cat']);
}

If I go to …/post-new.php?post_title=testing&content=testing2&tags=2014&cat=1, I get my title, content, tag, and category pre-populated. Only missing the slug/permalink.

Currently, I’m not wanting to use the XML-RPC method…

What I would like to do:

I would like to generate a page dynamically from a user’s response in a form. The user would then be presented an editor where they can make final edits before publishing.