James; nice brushwork!

But I can't get over how far the WotC Yuzzem mini is removed from how I originally imagined them

Akula: Yuzzems are from one of the first Star Wars novels; Splinter of the Mind's Eye. It takes place somewhere between ANH and ESB and possibly was a screenplay originally.
It details the exploits of Luke and Leia (pre-revelation, so a bit awkward in some scenes

) on an Imperial planet where they get into trouble with Imperial forces whilst undercover. Leia ends up in prison, and befriends two Yuzzem in the same cell, who then help her and Luke find the Splinter of the Mind's Eye (a Force enhancing crystal), while being chased by Darth Vader through the jungle.
Pretty cool book; I read it somewhere in the eighties and until Heir to the Empire, it was the only Extended Universe novel next to Han Solo at Star's End.