The file you get was called "catherine" will all the art files inside, right? I think what I did was I just moved the "catherine" file under the "art" file in "assets". I just checked the Mod, and it seems like you will have to add a new folder called "leaderheads" inside the "art" file for the "catherine" file.
If that doesn't work, you can always change the art direction manually in the LH Art XML File.