"Are we men or lawyers?"
Translation:Siamo uomini o avvocati?
Uh? No that's nonsense. Italian isn't like English, French or German. The question is given only by the tone of the voice and the obvious question mark, no swap between verb and subjects. There are some rare cases like, for example, you're in a room with someone, you hear a noise and asks the other person "was it you?" which it translates as "sei stato tu?". But again, it's an exception.
"O"/"oppure" are synonyms. They all mean "or", there's no rule for using one instead of the other. Examples: "Vuoi una mela o/oppure una pera? --> "do you want an apple or a pear?" "rimaniamo o/oppure andiamo via?" --> "shall we stay or go away?"
There are, though, some statements/common saying that are always used with "o" for example "sooner or later" in Italian becomes "prima o poi", you'll never hear someone say "prima oppure poi" even though it's not grammatically wrong, it just doesn't sound right. The famous Hamlet's quote "to be or not to be" is always translated with "essere o non essere", for instance.
There's also a third word, "ovvero", which has the same meaning of "o" and "oppure" but in spoken Italian is almost never used. It is highly used in legal language.
"Ovvero" can also be used with the meaning of "ossia" which in English gets translated as "that is", with this meaning is a bit more common in spoken Italian.