I am unfamilure with moding Civ4. I can try but am not really to versed at much modding.
Yes, you have done some quick research! lol. Well, the methane breathers didnt have much in the way of names to draw from, nothing to really use to fill in their culture, where-as the others do have a vast cultural tradition.
Here is a naming list I found on the internet of character names found in the series, and it gives a hint as to the culture and languages:
http://www.perrochon.com/cherryh/ref/p_compac.html
In the book series, the Hani belong to a homeworld called Anuurn, and there are two principle contients there, Enafy and another I cant recall at the moment. The impression one gets is that Anuurn represents a planet sized "African" contient. So, in my mind I imagine the Mali culture as representing the Hani, possibly even the Egyptians.
When you say incprporating art work, I dont know what you mean. I was thinking simply to rename the leaders and cultures, and giving a new city naming list. But if more is possible, then that would be grand indeed.
Additionally, in the Chanur series, the species each have a sphear of influence in space, with maybe 10 to 15 star systems in each sphear. I was thinking the senerio could simply have maybe 5 super contients representing the different sphears, and plant the cultures on them.
What you are thinking of 2 to 3 cultures per species would be great, and then to plant them on the 5 contients would be grand too!
I can fill in more on cultures and such, I have to drag out my books. Might you be interested in aiding me on this?