By my experience with mogas and pokemons, this is 100% NOT efree (efree is an elemental moga, it's burning, can't be on her neck in first place xDD). In my opinion this is a SAND moga. And yeah.. it will appear eventually. It might be a beginner though... the first moga Nova started with. Like Picatchu to Satoshi/Ash...
I think it may look like the sand-pokemon Sandshrew... maybe she (if it was a sandshrew, and I know it isn't) went to kanto/sinnoh and caught one before she found the mogas, or maybe killed a sandshrew that was trying to kill Hanzo, and she has it around her neck as a trophy? haha,lol!