I do like the way they showed the axle sticking out of the Piraka's head.
Now make her insane duplicate.

Well the other artwork they did seemed to be Bohrok as cute chibi anime girls, and this one seems to have long lashes and more prominent lips that most boys drawn in this style I would expect. I also always saw the bumps on the chins of vezok and hakann in set form to look similar to male stubble (which here is designs on the collar). If I were making them a male humanization I would have made it their chin with actual stubble and/or beard.

However, you are correct that there isn't anything definitive showing what gender the drawing is so perhaps I am wrong.