Disabling Polylang, with this active, kills WordPress

If you disable Polylang while this plugin is active, it crashes WordPress badly enough that you can’t even get in to disable it.
(We have a client who wanted a bilingual site, but now won’t have the translations done in time to go live, so will add them later.)

I’ve fixed it locally by adding the following checks.
admin/String_Registration.php
At the start of the function register_strings_from_array_recursive()

if(!function_exists('pll_register_string')) {
	return;
}

inc/Helpers.php
At the start of the function load_string_translations_textdomain()

if(!function_exists('pll__')) {
	return;
}

It’s also nicer if it can strip out the curly braces if it’s not active.

inc/Helpers.php
Remove from the start of the function translate_translation_strings_recursive()

if(!function_exists('pll__'))
	return $text_or_array;

and replace with
$use_pll = function_exists('pll__');

then in the foreach loop, replace
$text_or_array = str_replace('{'.$string.'}', pll__($string), $text_or_array);

with

$replace = $string;
if($use_pll) {
	$replace = pll__($replace);
}
$text_or_array = str_replace('{'.$string.'}', $replace, $text_or_array);

Thank for the plugin. Would it be possible to add something like the above?