Could do. But you'd think a "demon" wouldn't need such a thing. That serum issue is the one thing I just can't come up with a legit story reason for.
Another thing that is bugging me. The Chameleon said in the end of Hunted after Kraven's funeral, "You needn't worry. The world is no longer your burden. Besides, there won't be much of it left soon...Not by the time I've finished." Well, Chameleon hasn't exactly made good on that, has he?
Other than that, I agree with your initial theory. Especially the "confession part". It struck me why Harry/Kindred didn't just say what he wanted Peter to say/realize. The fact he legitimately couldn't do so as a "demon" of sorts is something that never crossed my mind.