How to override specific functionality in WP-Property?

Everything in template-functions.php is safe to override, just create a function with the same name in your theme's functions.php file.

If function is wrapped with if ( !function_exists( 'name_of_the_function' ) ): it means that if that function has already been declared somewhere else (e.g. in theme) we will not try to use our function but the custom function will be used.