How to modify loop hooks properly with genesis_custom_loop()

Genesis comes with a useful function called genesis_custom_loop() to output elements like entry header, entry content and entry footer when you want to write a custom query. If you would like to make any changes like showing/hiding certain elements in the loop or moving them around, it is not sufficient just to do so and call the genesis_custom_loop() with your query arguments. You also need to remember to undo or reverse your actions. Not doing this will affect other loops and may have undesirable consequences. In this tutorial, I illustrate this with an example of displaying 1 latest post from a portfolio custom post type below the header on the front page. We will first create a function based on genesis_do_post_image() to display linked (to the entry permalink) image in a specific medium_large size. Then in a function hooked to genesis_after_header, we shall

1. specify the CPT name, the number of posts to be fetched in an $args array and set no_found_rows to true to speed up the WordPress query ¹.
2. add a custom featured-portfolio class to the entry for easy CSS targeting.
3. do these loop actions: replacing Genesis archive image with our custom one, relocating entry title from entry header to entry content - above the content and removing the post info.
4. run genesis_custom_loop with $args.
5. reverse the custom loop actions.

Here's the code in child theme's functions.php that does the above: