The coins on famous people, can they be harvested as a resourse? Also, an example of city battle would be helpful. We were under the impression that the +12 city strength added to the attack power of the units involved but did not increase the units health. After reading a few threads here it sounds like we were not even close! Thanks for any help!

Coins are never harvested. As long as you have an unblocked great person with a coin in your city your have that coin. As soon as the great person gets blocked, killed, or removed for any other reason you lose the coin.

City battle works like any other battle, except the defender always gets six cards. Possibly one more from government. The city bonus is calculated before the battle, along with any other bonuses from great people and buildings. The player with the higher bonus adds the difference to his surviving units after the battle. The higher total wins.

Edit,

I found what I was looking for.