When the second noun can be seen as a name, a lablel or a title of the first, you can leave the preposition out. Exemple:

• La stragégie Mitterrand: if the sentence would see Mitterand as the author, it would be “La stratégie de Mitterand”. But Mitterrand is seen as the name given to the strategy.
• Les années Poutine: if the sentence would speak of the years in Poutine’s own life, it would be “Les années de Poutine”. If it would be about the time under his régime, it would be “Les années sous Poutine”. But here Poutine is seen as the name given to these years, a kind of title. .
• Responsable qualité: if the sentence was about someone ordinary in the company who is in charge of the quality, it would be “le responsable de la qualité”. But here “Qualité” is understood as title of a corporate function or a department. So you’d write “Le responsable du service qualité“. But by extension the name of the department, is also the label that identifies best this management post
• Projet “Recherche & Développement”: same as above: R&D is a function. And the name of that function identifies the project.

Now in your list there are also some other cases:

• “débat-marathon” is in principle a compound noun. So it’s the same principle than “code-barres” or “roman-fleuve”. I think it’s a tolerated practice to leave the dash out, using marathon as if it were an adjective.
• “projet recherche” sounds weird to me if taken out of a context in which “Recherche” would be understood as a title or a name (for example the title of a department in charge, or the tile of the project like “le projet POLARIS”)