The urge to red ink that sentence is so strong.
To answer your question, no one.  I have a hard time believing you actually have all these questions unless English is not your first language.  My reply was serious.  You are best served by reading an appropriate textbook.
I understood your initial question, but once you veered off into "boys/boys' basketball" referencing the actual BALL instead of the team or sport, you lost me.  When you threw "men's/mens'" (it hurts to type that) into the thread, I figured you were pulling our legs.  Perhaps not.  But if you truly do not understand that "men" is already plural and thus, requires no "s" be added, then reading a textbook might be the best course of action.  No snark, just fact.
No pee or Cheerios either.