What is the best app for tracking family members?

We are planning to track our 2 family members - One is a 15 year old daughter and the other is a 5 year old son.

Both have iPhones. Our goal is for them to not be able to delete, install apps or use any other way to make us unable to track them. We will share screenshots and video of their iPhone screen throughout the day, so we can see who they are doing stuff with, what games they are playing, etc. We want to stay on their phones (except to take pictures) and be able to view their location. We just want an app that will keep them under control. We don't have any kids yet, but we wanted to learn from the mistakes we made with our son (he was on an iPhone with no parental control).

You may want to look into some version of FamilyLocator. It doesn't allow you to track a person by location, but you can see who has contact with them (and for how long) and have reports of what the person did last and where they were at the time. They also have a family group feature to share your location with other family members as well.99, and will likely do everything you want to do.