You could model in anim8or and probably get the models into CS somehow. To do this you'd have to use an exporter someone else uses that could export to a correct format. Or, you'd have to get a program that can export to the CS format, and export from anim8or, import to the other program then export again. I believe someone wrote a C++ format that can export figures and perhaps animations recently, but there are hardly any of those (that work with animations).
So if I were you, search around the forum and google for anim8or exporters that export to a useable format. A lot of it will be a learning experience though, remember that. We don't have all the answers because we haven't tried before! But I'm sure it's possible in some way.
Edit:
http://www.anim8or.com/smf/index.php?topic=382.0Check out that thread, I'm sure that this could be very useful. Still, I don't think it will be able to be done with anim8or alone, you'll need export programs to get the models into the games.