All those words are a variety on a theme, Eve.
From my Dutch to English Van Dale dictionary:
Knurft (de (m)):
nitwit, nincompoop, blockhead, fathead; (BE also) nit, wally, (AE also) nerd.
Kazakkendraaier is a turncoat. It originates from French (googling: "tourner casaque"): somebody who suddenly changes his standpoint on something and does the opposite of what he said the day before.
I know the words "mazzel" and "mazzelaar" from Dutch tv but I didn't know "mazzelpik". A boy or a man will sometimes refer to his "pik" here but I'm guessing it's not the same pik we're talking about.