How can I stop that information from being edited by the manager

Also, my second concern was not addressed. How can I stop that information from being edited by the manager?

You can add the Get Form Page URL widget on the form. Then you can create conditions, which will disable some fields when the edit link is used. So, your managers will not be able to edit those fields.

Your conditions should look like this:

Let us know if you need any further assistance.