Hey there smorrison0,
Thanks for reaching out to Apple Support Communities. I understand you have some questions about hiding apps and how this works with Family Sharing. I’ll be happy to help.
‘When you hide an app, it won't appear in your list of purchases in the App Store. If you use Family Sharing, the app also won't appear in family members' purchases and won't be available for family members to redownload. But the app will still appear in your purchase history.’ For more info on hiding an App Store purchase, along with info on unhiding them, take a look at this link:
Hide App Store purchases
One way to keep the apps available to other family members while not letting your child access them would be to use parental controls on their devices. Take a look at this article for more info:
Use parental controls on your child's iPhone, iPad, and iPod touch
Regards.