I only need to meet 2 more goals for my family and can't seem to get them to get sick enough. I need "not just a virus" and "gravely ill". The most my little people get are headaches, stomach aches and other things solved simply. Am I feeding them too well and keeping everything too clean?

You're lucky! I don't think there's anything you can do. If a peep is going to get gravely ill it'll happen without any input from you. The only advice is to wait.