ANSWER:

You cannot monitor them 24/7 like this. You have done your job if you taught them the ethics of Islam and if they sin even after this, you are not sinful.

Restricting them from halal things and spying on them would only make them cheat and lie to you and also drive them away from Islam. 

As a parent to 21 yr old twins (boy n girl) Alhamdulillah I tried giving them knowledge of both the worlds so after this can I keep control of what they do? Like see who they are friends with , check their phones , ask them not to lock their room doors, not let them hangout with friends like other kids do. Girls aren’t safe these days so to have equality I don’t let my son go out too