So your explanation of the problem is a bit confusing...
Do you have an app restrictions profile or app control profile applied?
Hidden apps are ones which are not directly called - they are used within other apps only. So for example, you might have an app which asks the Camera app for a picture. In this case, adding the Camera as Hidden should work iirc.
For your purpose, you need the Web or Chrome apps actually added to the Launcher.
If you have already tried that, please let me know if other links work while the browsers are in the Launcher profile or not.