In the addtocart.phtml you posted, the product is saved to $_product rather than $product

<?php $_product = $this->getProduct(); ?>

You should be able to do

$_product->getId();

In the addtocart.phtml you posted, the product is saved to $_product rather than $product

<?php $_product = $this->getProduct(); ?>

You should be able to do

<?php echo 'See <a href="/catalog/product/view/id/' . $_product->getId() . '">created simple product</a>' ?>