-와/-과, -(이)랑 and -하고 all mean and when connecting two nouns and with otherwise. According to the link I post below -와/-과 is the most formal and -하고 the least formal/most colloquial.
is "eating banana together with coffee" a valid interpretation of this sentence?
for example if preceded by another speaker asking: "what are you eating?" or "what is that person eating?", wouldn't the implicit subject no longer be the speaker? or would a sentence like that have different grammer or additional words?