Note that you only have the right to sell your code. If you have contributions of others in there, you need to get their consent.
You are correct sir. However if applying that to the GNU part then permissions are automatically granted under the licence so long as the documentation is crediting it. As to other parties definitely, unless it is under one organisation umbrella in which case the company owns the license and not the employees.
Edit: This advice fails to take into account 3rd party contributions under the GPL utilised - spoken of later in the thread