Дмитрий

function foo($args1, $args2) {
    $html = '';
    foreach ($args1 as $val) {
        $html .= $val;
    }
    return $html;
}

echo foo($args1, $args2);

$user = [
    'id' => 1,
    'name' => 'Ivan Ivanov',
    'role' => 'developer',
    'salary' => 100
];

$apiTemplatesSet1 = [
    '/api/items/%id%/%name%',
    '/api/items/%id%/%role%',
    '/api/items/%id%/%salary%'
];

class Invoker
{
    private $data;

    public function __construct(array $data)
    {
        $this->data = $data;
    }

    public function __invoke(array $key): string
    {
        return $this->data[$key[1]];
    }
}

$function = new Invoker($user);

$result = array_map(function ($key) use ($function)
{
    return preg_replace_callback('#%(.*)%#isU', $function, $key);
}
, array_values($apiTemplatesSet1));

echo '<pre>' . print_r($result, true);

$balance = json_decode($json, true);
echo $balance['result']['balance'];