I am not positive how this plugin will work along with this function as I’ve never tried it, but you can probably find everything you need by looking in this file:
advanced-custom-fields-font-awesome/fields/acf-font-awesome-v5.php
$this->name = 'font-awesome';
$this->label = __( 'Font Awesome Icon', 'acf-font-awesome');
$this->category = 'content';
$this->settings = $settings;
$this->defaults = array(
'enqueue_fa' => 0,
'allow_null' => 0,
'show_preview' => 1,
'save_format' => 'element',
'default_value' => '',
'fa_live_preview' => '',
'choices' => $this->get_icons('list')
);
Where you might run into trouble is the ‘choices’ part of the parameters as this is not a fixed list, it is retrieved programmatically so that it keeps up to date with FontAwesome releases.
You will see that there is a filter you can use though to get the icons, check out the get_icons() function in that file for an example of how it is used.
Hope this helps,
Matt Keys