Just a quick Q.

When attacking, do you get any defense bonus from the tile you attack from?

EX. attacking a city from a hill...

No. The terrain defense bonuses only apply when defending. Think of each tile as a huge tract of land. When you're attacking from a hill into a plain, your troops are actually leaving the hills and entering the plains to attack an enemy. They have left the hills by the time they make contact, and therefore do not gain any bonus for being in the hills.