Ball of Wax

Actually under reading up on copyright law. As the copyright holder of the additional code. I can chose to redistribute that code under a more or less restrictive license as long as it does not contain any incompatibly licensed code within its whole, regardless of any and all clauses defined within said licenses (including a strong copyleft). However if any of the code that I am not the copyright holder of, were to remain then the it would be unlawful for me to release it under any license that violates it license.

At least, that is as I understand it.