I have never been able to track down what "cnoeppkes" is supposed to mean.
Not quite. The -ke ending here is just another regional variant of the diminutive. The s at the end is a colloquial plural form.
So the transformation from German to this weird german-english would be:
Knöpfe - Knöpfchen - Knöppkes - Cnoeppkes
https://en.m.wikipedia.org/wiki/Jim_Knopf
And the article is interesting anyway.