I would like to help you get these issues worked out but it would be best to concentrate on a single part of this at a time.
Currently when you are going through your checkout are you able to get to the confirm page and see all of the values there? If not what values are you seeing? If there is a problem showing these values please post back with your checkout and confirm pages in a zip archive minus any sensitive details.
If this is not the problem and you can see the confirm page with all of the details what happens when you try to confirm the order?
Weather or not you store any of the user information should not have an effect on how the checkout performs.