how to extend the "Application Templates" of MOSS

Question

For example, MOSS provides "Inventory Tracking Template"

1. To add workflow capability should we create another custom webpart using the classes?

2. Hope we can add columns to the List Provided. in order to add additional logic (like validation, kicking notification,etc)

   Visit this link to understand more about the 2nd point:

   http://www.experts-exchange.com/OS/Microsoft%5FOperating%5FSystems/Server/MS-SharePoint/Q%5F24228958.html

Thank you for any pointers/articles/Forum posts on the best/recommended practices