I would also point out another issue with the theory that minimum wage increase in Seattle has backfired because minimum wage workers have had their hours cut more than their per-hour wage increased:
If this was actually the case, wouldn't this be a huge win for the companies? They're getting by with less workers and less money paid out! That's pure profit! Every right wing pundit should be all for it
(BTW, there is actually plenty of evidence that increasing minimum wage does consistently end up increasing overall economic efficiency, exactly because so many employers are stupid and will continue to throw more cheap labor at problems instead of actually solving them, if they have that option.)