I have been through your tips http://codex.wordpress.org/Child_Themes and tried to implement the related information.
So far, I could get some result onto "simple thing" ..: Adds a favicon link to the head element of HTML pages.
"So far" means I could see my icon only on the home page of the Child theme and only by using G-CHROME, MSIE keeps showing the wp-theme favicon.ico default.
Regarding your assertion: "TIP FOR THEME DEVELOPERS. The fact that a child theme’s functions.php is loaded first means that you can make the user functions of your theme pluggable —that is, replaceable by a child theme— by declaring them conditionally. E.g.:", well, I would say that is not really exact ...more: "In that way, a child theme can replace a PHP function of the parent by simply declaring it again."
functions.php file of the child theme is not loaded first, but it adds/encodes functionality if any is not included in the suite of Atahualpa.
After I matched the whole path to put my safe directory (safe from being deleted by updating) I get the following error: "Fatal error: Cannot redeclare bfa_rotating_header_images() in /home/knowk/public_html/ads/wp-content/themes/atahualpa/functions/bfa_rotating_header_images.php on line 2"
The error informs that the Atahaulpa function was loaded first than my php included file into the functions.php.
The easiest way to get the images back after each updatng is to edit the file: "bfa_rotating_header_images()" in this way: " ...
################### images in /images/header/ (on regular WordPress)
$files = "";
$imgpath = get_template_directory() . '/child_images/';
$imgdir = $templateURI . '/child_images/';
$dh = opendir($imgpath);
Please advise if you have any solution.
I suppose that Atahualpa should really resolve this issue, if the child implementation is a requirement of yours for whoever adds a theme for WordPress.