Uncle Ben, you keep deliberately mixing up salaries and wages. A monthly rate is not a wage, it is a salary. Since you say their contract does not specify an hourly wage, but a monthly salary, that means they are salaried employees and they do not get an hourly wage, so there cannot be a minimum on it. The federal minimum salary is $23,660 a year, and I’m sure they’re getting more than that.
The amount of the monthly check when multiplied by 12 and divided by # of hours worked over 10 months equals the $15 minimum wage.
Interesting arithmetic, but utterly irrelevant. Salaries don’t work like that.