What sub-story? I already stated they were'nt in the game, This was for speculations, Nash is'nt a main-quest important character, Primm is'nt a specific town which spoils a part of the game.
So.. Your point?
Sub-Story: The 6 couriers and the one potential courier that turned down the job.
Nash: On first playthroughs, it's likely that you will talk to Nash before speaking to anyone inside primm, where he will point you to another character that is also important to the main quest. Yes, you can completely skip him, but that's optional. That would be like saying the Vulpes Inculta, Manny Vargas, or Jessup had absolutely nothing to with the main quest, which they all do. A minor role, but it's there.
Primm: No, it doesn't spoil the main quest, but there is a few other quests that involve/revolve around that town, quests that can be spoiled.
Too far off topic, you won't listen to reason, I'm done replying to you.