In both cases, Principle-Agent assumptions apply, but not because both are based on for-profit assumptions.
the third sector, its definition and description is missing. I would not have thought of this as a major issue unless Evers and Laville (2004) The third sector in Europe, Edward Elgar, spesifically discuss whether cooperations are defined within or outside the third sector. Maybe taken for granted here? The least we should expect is a definition.