Young skunks can spray by the time they are 7-8 weeks old, about the same time as they start going outside of the den to learn to forage. Most skunks give birth in May or early June. So depending on when she had them, you may have young skunks wandering around the area when you have your party. The fox urine isn't going to do anything. The skunks will totally ignore that. Your best bet is to hire a nuisance wildlife control operator to trap and remove the skunks.