Will dequeueing in child theme functions.php file prevent Google Fonts from loading?

Dequeueing the enqueued style will be sufficient. But you need to be careful to dequeue it after it is enqueued. It is enqueued at the default priority of 10, so make sure that when you hook into wp_enqueue_scripts you do so at a higher/later priority.

add_action( 'wp_enqueue_scripts', 'wpse_escutcheon_scripts', 11 );
function wpse_escutcheon_scripts() {
  wp_dequeue_style( 'escutcheon-fonts' );
}