Okay here me out. I think this new evolution of Rockruff maybe possibly could confirm it as the new Eevee, covering the types not represented already by an Eeveelution. Base form is Rock. Evolves into a Rock type during the day and a FIGHTING TYPE at night.

EdgeRuff is a FIGHTING TYPE. Why else would they stress that it uses Counter specifically. The other types will come about with evolving Rockruff while holding a specific Z Stone. I'm certain of this.