I want to most efficiently use array values and variables in a WordPress template while abiding by PHP/WordPress best practices and standards
I would not use the pkav function. Beside the fact that the name means nothing (which was stated in the comments) it also restricts the default value to false.
This is wrong when you might expect strings or something else for a certain variable.
From the looks of it, the footer text and button vars look like strings.
I would go with this
&lt;?php
    $options = get_fields('options');
    $footer_text = $options['footer_text'] ?? '';
    $footer_button = $options['footer_button'] ?? '';
?&gt;

I would also go with declaring all variables at the top of the file. It makes the code more readable and will allow a frontend developer to focus on the html part instead of trying to navigate in the if statements.
&lt;?php if ($something) :?&gt;
    &lt;div&gt;&lt;?= esc_html($something) ;?&gt;&lt;/div&gt;
&lt;?php endif;?&gt;

is easier to read than
&lt;?php if (!empty( $options['footer_text'])) : ?&gt;
    &lt;h4&gt;&lt;?php echo esc_html($options['footer_text']); ?&gt;&lt;/h4&gt;
&lt;?php endif; ?&gt;