I assume that municipalities which span multiple counties can be split along county lines with no penalty, since your Wisconsin map does just that in several spots. (And it might make following the Michigan Rule literally impossible in some cases otherwise.)
Though the rule is usually stated as don't split counties unless necessary, and then don't split municipalities; the underlying principle is to not split the lowest-level communities.
So I would adjust the county boundaries to match municipality boundaries, placing the municipality in the county with the most population.
