Roles in 2.1.2 vs our custom roles

In 2.0.1 we created custom roles for student, instructor and tf (named 
using the same case as shown) and now in 2.1.2, there are stock Student, 
Instructor, TA roles.  Are we required to use these roles or can we 
adjust our existing roles to have the same permission types as the OOTB 
roles and then delete those roles from  !site.template.course.

The reason I ask is that I know that now every site must have a 
maintainer (which is a problem for us because we don't include the 
maintain role in our course sites, but that's another issue.

What are the 'required' roles OOTB for 2.1.2 and can I safely continue 
to use our 'student', 'instructor', and 'tf' roles.  (maybe I should 
rename them using the upper case lettering before converting our 
existing database to be 2.1.2 compliant?

Thanks in advance.

Cheryl

----------------------
This automatic notification message was sent by Sakai Collab 
(http://collab.sakaiproject.org/portal) from the DG: Development site.
You can modify how you receive notifications at My Workspace > Preferences.