Where in the modular loading file structure do I add flavor units?

I'd like to add flavor units to the Ethnic Citystyles module, but I'm not sure where in the folder structure they should go. At the moment, I've added two of StrategyOnly's civ modules and one of Amra's and they work. So it seems I could add "custom civs" for every civ I want to add flavor units for and that should work since I can just copy the folder/file order that the three working modules have. However, I'd like for these flavor units to be a separate module that can be enabled/disabled easily and so used with other mods, such as Next War or Gods of Old or even just standard unmodded BtS. Is adding multiple "custom civs" the only way to do this?

Also, in A Modders Guide to Beyond the Sword, Kael mentions he has provided clean templates for modders. Where can I find these?