Are derivative classifiers responsible for carrying forward guidance about when the classification of information may be downgraded and when it may be declassified altogether?

Yes, derivative classifiers are responsible for ensuring that classification decisions are consistent with established guidelines, including the timing for downgrading or declassification of information. They must be aware of the original classification authority's guidance regarding the lifespan of classified information and apply that knowledge when determining the classification of derivative materials. However, the ultimate authority for declassification decisions typically rests with the original classification authority.