The receive and submit is built into InfoPath. If you setup a receive or submit connection it will handle it appropriately. These would each be a seperate datasource usually.
Workflow is very easy to build into your form as long as you track the form state and the user. I use an active directory web service to ID each user and say their manager, email, department, location etc from AD.
It sounds like you are researching or ramping up on InfoPath. It can do just about everything most people need.