It's not clear to me why you can draw conclusions about the impact on employees from the UW study. I read it as "minimum wage increase hurts small employers more than big ones", which is less headline-worthy.
I worked in Seattle at minimum wage through this for a "small employer"(this term isn't very nuanced) who was still a millionaire and making huge profits. More significant than the cost of any wage hikes he was experiencing is the skyrocketing real estate market here. This doesn't even begin the discussion on the concern for the welfare of employers who complain that their large profits are being hurt because they can't squeeze dimes from poor people as easily.