Hi bsmith. It would not surprise me if the Fusion model would fit, since there are probably minimal/no differences in the window frames of the two vehicles. Could be a difference in glass thickness/weather seals though, if the MKZ has thicker acoustic glass. However, that is only an educated guess, and it could be a wrong guess. And since they are not listed, there is no way to be sure before you purchase.
Just an idea: I would recommend reading the return policy listed on the WeatherTech website or calling (yes, unfortunately you will need to wait) and see what their return policy is. If you can return them for a refund (or credit, if you think you may purchase something else in the future), then purchase, test fit and you'll see for yourself. If they will only perform an exchange if defective, then it is not worth the chance.
If you can return for a full refund/credit and they fit, that is great. If they do not fit, return them for the refund.