Hasn't Cedric also said something along the lines of "I don't know the upcoming story" before as well? Something about how he likes to discover it so he's purposefully left in the dark about this stuff.
Regardless, even if we assume what he said is correct, the training could also just be training for what comes after the events of Extinction, when all the Arks have landed and unleashed their life on the planet.
The two biggest points on the timeline question are the lack of notes on Extinction and Helena's change.
I thought about it and decided it's unlikely that Helena had simply learned how to represent her face by Extinction if she couldn't already, since she could make HLN-A which would be much more difficult, so therefore the loss of the human-like face is a strong indicator that time has passed and that it's after Extinction.
On the flip side, the lack of notes on Extinction would imply that it's before Extinction. HLN-A said outright that she wanted to learn more about Helena so it makes absolutely no sense for her to completely ignore Extinction, where plenty of significant things happened to Helena.
It's tricky because if I were to look at just one of these reasons without knowing about the other, I'd be completely sure that the idea it supports is definitely correct, but here they both are, sitting there, bothering me.
It's hard to work with two ideas that so strongly contradict each other, something must be missing here in one of the reasons. The only logical explanation is that one of the assumptions made from the evidence is wrong, but I don't see how.