I cannot answer your specific questions, but have a couple of observations which might be helpful:

1. If you can fly out of EWR, take a look at Emirates' nonstop EWR-ATH service.

2. If you have -- or decide to acquire -- an Amex Platinum card, be advised that both Delta and Emirates participate in Amex's International Airline Program, which sometimes offers special, reduced Business and First Class fares on international flights booked through Amex Travel.

Good luck!