I don't have any experience with the law in Minnesota but the specific statute under federal law is (emphasis added by me) ...
"An
exempt employee must receive the full salary for any week in which the
employee performs any work without regard to the number of days or
hours worked. Exempt employees need not be paid for any workweek in
which they perform no work. An employee is not paid on a salary basis
if deductions from the employee's predetermined compensation are made
for absences occasioned by the employer or by the operating
requirements of the business. If the employee is ready, willing and
able to work, deductions may not be made for time when work is not
available."
When exempt employees are willing and able to work but the employer has no work for them, they must be given the entire workweek off in order for the employer to avoid paying them their full salary. Conversely if an exempt employee performs any work in a workweek (such as checking email from home for an hour) then he or she must receive their full salary. So it's important to tell exempt employees that they are prohibited from performing any work (including email) during the workweek of the furlough.
Another issue is unemployment benefits eligibility. Look at your state law to see whether furloghed workers will be eligible for unemployment compensation during the furlough. If they are you should give them information on how they can apply for benefits.