could the NAACP keep her in some (unpaid) role?
Depends if she really cared or saw it as a career opportunity somehow to take advantage of positive discrimination? I can't think of any reason someone can't stand up for others rights without needing to impersonate them.
I can't tell what the deal with the parents is but she apparently cut them off. She had a number of adopted black siblings - maybe some issue there (jealousy or impersonation for some reason?)