There is no such thing as creating a user or a project that is exclusive only to Lab Management. Therefore, if you create a user in CEE, you have created a CUBiT user and the same principle (and action) applies in deleting that user.
Similarly, there are no user roles or permissions available to users inside of Lab Management that are not set from CEE. All roles and permissions are assigned inside of CEE, and Lab Management references them as needed.