this one is taken from the Glossary compiled by Pete Saussy

I take this to mean one of the versions of this book by George Stone Saussy III (aka Pete Saussy): The Oxter English Dictionary: Uncommon Words Used by Uncommonly Good Writers, The Logodaedalian's Dictionary of Interesting and Unusual Words. Or is there an online version of same? From what I gathered online via Google, Mr Saussy researched all his words in the OED or such-like. It may be a typo. From your site, he seems to have been in contact with you, why not ask the man himself?

I am a fan of macaronics, but I have not run across the word before, and mingle mangle seems more like a gallimaufry or hodgepodge than macaronics per se.

Ceci n'est pas un seing.