I think my answer in the previous post might have been slightly incorrect in English and therefore confusing you. I personally don't make a real difference between "Nobody arrived" and "Nobody has arrived", and I think that's were I'm wrong. Actually, the real meaning of "Personne n'est arrivé" depends of the context.
You could be telling a story that happened in the past :
J'attendais mes amis mais personne n'est arrivé.
-> The action was in the past and is finished, nobody did ever arrive. We use "imparafait" because it's an action that spans over time. I would translate this to :
I was waiting for my friends but nobody (ever) arrived
but I guess it could be translated to
I waited for my friends but nobody (ever) arrived
I couldn't tell if both translations have the exact same meaning though, I would maybe mistakenly use either one or the other without further thinking.
You could also be telling about something happening now :
J'attends mes amis mais personne n'est (encore) arrivé.
-> The action is in the present, I'm still waiting, and nobody arrived hitherto (and if anyone had arrived, that would have been in the past from now, so we use "passé composé"). I would translate this to :
I'm waiting for my friends but nobody arrived (yet)
I'm no translator nor French or English expert, but I think tenses in French and English just don't always have a direct translation and that may lead to some confusion. French doesn't have "continuous" tenses for example. Taking my example from previous question remark :
Je bois de la vodka
could be translated to "I'm drinking vodka" (=> right now) or "I drink Vodka" (=> usually; I've nothing against vodka as a general matter)
As of the difference between various past tenses in French, I think those 2 schemas combined summarize it well :