The actual number is a bit higher, but after some mandatory social security/pension contributions to switzerland that is pretty much what is averages to. You have to also remember that for 1000 for housing a month in greece you live like a king. With 500 all in you can get a very decent furnished flat in a great area.
This is indeed for FOs, I dont remember the captain numbers.
In the summer you will 100% certainly get over 75h rosters. If you want to its easy to swap your flights to reach higher numbers even if the roster ends up at around 75.
I think the initial contract is 2 years, then 1 year renewable.
EDIT again. Bases in the winter really only Athens for expats. Summer you have Rhodes, Heraklion, Larnaca, Kalamata, Thessaloniki from the top of my head, you can also ask to mix these up and do different places. For FO its usually for the second summer though.