What Chet Knows [Extreme Spoilers]

[HSuperLee]

So the past few weeks I've been thinking about this book a bit, and one thing I keep coming back to is the reveal of Chet being a delver, and the consequences of that on Chet's character and knowledge. Most notably, that Chet knows things Spensa doesn't. It would be one thing if all Chet's knowledge came from seeing Spensa's mind, and would explain some of the knowledge of stories and language, but Chet teaches Spensa knots and survival skills. So did Chet copy Commander Spears's memories and rely on those for his interactions with Spensa? Or did the original delver retain its knowledge even while it deleted its memory and personality (which I'm not sure makes sense or would be possible). Basically, I'm creating this thread to discuss where Chet's knowledge came from, and how much of it is shared among all the delvers.