As ThinkCanvas said, I`m most certain that you will need to file the DBA names for your other two business entities. Your LLC can own these, and you can put at the bottom of your web site that the site is owned and operated by XYZ, LLC. This will help clarify that the billing in going under the LLC name.
We were going to go by a different name for our business and file a DBA for it owned and operated by our LLC. We`ve decided to go with our LLC name instead so we never filed it. I think regardless of the state, if you are operating a business under a different name (even your own) you need to file at least a DBA.
The type of business entity you form (C corporation, S corp, partnership,...etc) is an important decision which has tax ramifications.
When you form a corporation you are creating a separate entity, which has a "life" of its` own.
There are legal, liability, financial, and tax reasons for the various business forms. You should consult an attorney and or tax accountant to determine what business form is best for your situation (current and future).