OK, I can see where you are referring to here.
I am trying to go through and reproduce the issues you are reporting, but cannot.
if I use one coupon and checkout, then create a new order an checkout using a different coupon, it is showing the correct coupon name for me.
you could try adding the following code on the checkout success at the very bottom:
<?php
if(isset($_SESSION['WA_Ecart_Coupon_ID'])) unset($_SESSION['WA_Ecart_Coupon_ID']);
if(isset($_SESSION['WA_ECart_Coupons'])) unset($_SESSION['WA_Ecart_Coupon_ID']);
if(isset($_SESSION['WA_Ecart_Coupon_Name'])) unset($_SESSION['WA_Ecart_Coupon_ID']);
if(isset($_SESSION['WADbSearch1_coupons_Results'])) unset($_SESSION['WADbSearch1_coupons_Results']);
?>
this will clear any coupons that are applied on success.
I am also not able to reproduce a problem where a coupon applied to certain products is applying to all. Maybe you have applied the coupon to the category? Testing a coupon that is applied to only one product, I can see in the cart line item details that only the price for the intended product is struck through and adjusted.
In my initial reply, i gave instructions for how you can add the coupon code used to the email. You could also adjust the code in the email to use the same order number as the success page.
