That's what I was afraid of Buying combat unit with faith (which represents summoning) is an important aspect of my mod, so I need to force the AI to do it using Lua.
The CP AI knows how to faith-buy military and non-military units, might look at copying that data from the CP if you want (or just use the CP as your base). The VMC is part of it, along with its glorious events.
Techs and Eras
The DLL expects to find ERA_ANCIENT, ERA_INDUSTRIAL and ERA_MODERN (industrial via hard-coding, the other two via the PostDefines table) - but you can rename them as anything eg "Early", "Middle" and "Late", but don't change their Types.
Whoward, didn't Pazyryk have a tutorial thread on how to check through Lua whether any of your SQL failed to load? That could be pretty useful here (and I can't find the thread!!).