I need some help in planning a trip and in maximizing miles. Leaving from JFK to Sao Paulo (GRU), I have been told the best carrier to travel with is JAL. I do not seem them as belonging to oneworld. Can someone please clarify?

From GRU, I need to get to Buenos Aires. There does not seem to be any oneworld carriers performing this route. Any tips?

From Buenos Aires, its on to Mexico City. I understand that this is meant to be a hellish trip - especially when you are due in at the office the day you arrive. The choice seems to be: (1) EZE, MIA, MEX for a total of 14 hours on AA (in F class, so not too painful) or (2) EZE and a stop through GRU on a local carrier. Any suggestions on best way?

MEX to JFK seems to be another problem. Are there no oneworld flights carrying this route? Any help would be GREATLY appreciated.