This will help in adding new units:
This will help in adding the new civ, though this guide is a bit complicated. If you wanted, you could just open the Civ XML file and re-name a civilization...So you can re-name the Romans the "Vampies", change their diplomacy text, city names, aggression levels, etc -- all without doing any hard work. Just look in your civilization XML files. If you want to get fancy and add in a brand new civ and not replace an existing civ, and if you want your own leader image, etc, this might be useful:
This forum may be useful for your other questions. I'm not sure how to implement your specific goals though , sorry. Though they seem easy enough to do.