If it's Appert, we won't know until after the Amerks season/playoffs. They really have no reason to rush the decision. If they like Appert and what they have there, I could see them keeping him in Rochester for the time being.
My ever evolving wild guess/theory is that Ruff probably got in the ear with Pegula or said something Terry liked or something he disliked of the perception of Granato (since Lindy coached against him), decided to fire Granato, which was outside Adams plan/timeline, and there will be an immediate choice (Ruff) for a short term hire, so that Ellis gets more time behind the bench as an assistant, learns under Ruff a couple years or even one year, and then Ellis gets promoted to Head Coach, and Appert gets promoted to Assistant Coach so that Ellis has someone with some sort of head coaching experience he can lean into if needed.