Also, I perhaps missed a description of what was expected in reading part of the original post (OP), it appears that the expectation is that when using PayPal Express, that all information associated with making the purchase and retrieving the product is expected to be in a single email.

I do not believe that login credentials and purchase order information have yet been combined in a single email. Before considering it the next best thing since sliced bread, consider the potential security concerns of that being true... you make a purchase from a site as an account manager for a business and then forward the order receipt to a worker who now has the login credentials... not cool.

Anyways, the normal process for such a visitor to make their first purchase at the site using paypal express is that they would receive an email indicating that they are a new customer, an email for the password that was randomly generated and an email with the order details for a total of 3 emails... if they were to purchase again from the site using paypal express, then they would receive just one email which would be the order details...

Is there a possibility that in this "second" site, that the database has been carried over which includes information about this "purchaser" such that an account creation doesn't occur and a password wasn't generated?