Removing these fields will require a few steps:
1. remove the fields in Design view in DW
2. you need to remove the server side validation at the top of the page, this could be easily done If you have Validation Toolkit. For the check out page, you need to remove the validation on the confirm page as well.
3. you need to update checkout success page to not show these values.
4. you need to update the email being sent to include these values.
Removing those field manually could be a lot of work, do you own any of our extensions that could speed out process, in addition, I think some of the Gateways might require these fields, but I'm not entirely sure.
