1. Yes, its not that hard. Build up your economy and then fight, not the other way around. This is harder for the Sabeans, and the Steppe factions.

2. Do you mean hoplites? They most likely fought overhand due to the nature of Greek phalanx warfare.

3. Defense skill is their skill at defending themselves. Armour is based on clothes and stuff. They have drugged themselves up to the eyeballs and feel no pain and attack with a ferocity hard to counter.

4. See FAQ.

Infact, check the FAQ, they probably answer everything.