A successful addition to my theme to allow parent/theme failover of local JSON

acf-local-json-after.php

<?php
// Integrating Advanced Custom Fields:
remove_filter( 'acf/settings/save_json', 'settings_save_json' );
add_filter( 'acf/settings/save_json', function() {
    return get_stylesheet_directory() . '/Library/Acf-Json';
} );
remove_filter( 'acf/settings/load_json', 'settings_load_json' );
add_filter( 'acf/settings/load_json', function( $paths ) {
    array_push(
        $paths,
        get_stylesheet_directory() . '/Library/Acf-Json',
        get_template_directory() . '/Library/Acf-Json'
    );
    return $paths;
} );