DETROIT — Oakland County prosecutors want to expand the list of witnesses who may testify in the upcoming trial of James Crumbley, the father of the Oxford High School shooter, saying it was so traumatizing for some witnesses who testified during the shooter’s mom’s trial that they may not be able to do it again. James Crumbley’s attorney has filed a motion not to allow student witnesses to testify in his trial next month in Oakland County Circuit Court, saying it could inflame the jury and be prejudicial. But Assistant Prosecuting Attorney Marc Keast said due to the “emotional impact” of test…