Is there a list of required sociologists and studies that students are required to know?

There is no list of required sociologists or studies.  The endorsed textbooks use examples of studies to demonstrate concepts, factors, issues, etc.  The sociological studies are used to support or reject these concepts, and a student’s use of studies can indicate their own depth of understanding.  However, it is entirely up to the teacher which studies and sociologists they intend to use.  The markschemes indicate which are likely to be used, not what must be used.