Form Pre-populate with items from a db table

Yes, but you have to write custom code to do so. There are hooks and filters in place so you can customize Gravity Forms via PHP. You would write PHP to query the data you need and then populate the fields dynamically.

Currently no. Gravity Forms is primarily a general purpose form builder so while it does have order form capabilities with payment processing capabilities with PayPal and additional payment gateways we will be introducing down the road it isn't it's primary purpose so it isn't going to be as feature rich as larger applications that focus solely on ecommerce.