Possible Clues:

• McCallister of 'Montana Territory'
• With 55-Across, math exercise, literally
• N.B.A. coach Kruger
• Name hidden in "Hello, Newman"
• Chaney of thrillers
• Chaney known as "The Man of a Thousand Faces"
• Chaney who was known as 'The Man of a Thousand Faces'
• "Wolfman" portrayer Chaney Jr.
• General Nol of Cambodia
• Either Chaney