Well, i fear to animate the render settings over time will not be possible - and this is what you are asking for. Zhe only way would be to render only a part of the animation with the higher setting and compose that later. But i don't think that this is possible without noticing. Regarding copy and paste keyframes. Because of the way keyframes are handled i think this is simply not possible. A thing i often asked for at e-on. To copy and paste attributes - like position, material, ... Not implemented. I think with the next feedback i will ask again. Having this animation issue in mind.

One day your ship comes in - but you're at the airport.