Really? thought that "hunaak" at the beginning of a sentence had existential import (sentences like "there is a Santa Claus"). But, it English, "there is your coffee, Rosa" doesn't sound as if it means that: it's just a variant way of saying "your coffee is there, Rosa". Especially since, in English, "here is X" and "there is X" mean the same in a lot of situations: we can say either when we are handing a cup of coffee to someone, for example. Now in Arabic, hunaak at the beginning of the sentence does seem to have existential import. But English is different.
Presumably there is a way of saying "over there" in Arabic? Just as in French, "là" means ""there", while "là bas" means "over there... Ah, I've just checked with Google Translate, and it appears my assumption was wrong. It gives هناك, whether the English is "there" or "over there". So it would appear that Hassan was right. Unless a native speaker would like to contradict Google Translate.
No. "There is your coffee" involves being present and indicating the coffee. "Your coffee is there", you don't have to be in the vicinity of the coffee. You could have been talking about eg Omar's house, and said "your coffee is there" with no pointing involved, just a reference to previous vocabulary, ie Omar's house.