How do I add civilisations/units/technologies/&c to Vanilla from G&K/BNW?

I own the complete version of Civilisation V, including all
DLC, scenarios, maps, &c. While I enjoy some new additions to the
game, such as civilisations, technologies, and units, to be
honest, I do not care for the new Gods and Kings or
Brave New World features such as the World Congress,
tourism, espionage, or religion. The only genuine features
I like from them are the 100-point combat system and trade routes.

Still, I enjoy playing against Maria Theresa and Aschur-banipall
while building the Terra Cotta Army. The way to solve this
problem seems easy enough; copy the civilisations/units/&c
into vanilla Civilisation, with slight modifications for those who
have, e.g., faith-based unique abilities. How would I do this
in ModBuddy?

(Should it be relevant, I play Civilisation in German,
not English.)

It'd be a lot tougher than you think. You'd have to do a lot of reinventing the wheel with a lot of the unique abilities, unit promotions, wonder effects, etc.

I am aware that certain changes would need to be made (e.g.
Byzantium's unique ability). Buildings &c that provide benefits
to G&K/BNW features would simply not be transferred to my
modded vanilla, and unique abilities could simply be changed.

Taking the example of, for instance, Austria, which requires
no features to change, how would I transfer Maria Theresa,
the Coffee-House, and Hussar into vanilla Civilisation
from Gods and Kings?

TheRealMaestro said:

Taking the example of, for instance, Austria, which requires
no features to change, how would I transfer Maria Theresa,
the Coffee-House, and Hussar into vanilla Civilisation
from Gods and Kings?

Click to expand...

But that's just it, even things that don't outright use the new features of the expansions aren't so easily backported into vanilla.

In the case of Austria, the UA ability (permanently buying city-states) isn't programmed into vanilla. You'd have to check if the vanilla's lua supports a similar functionaility and completely program the ability from scratch or give them something new.

Even Austria's UU which provides a flank attack bonus can't be directly ported. The reason being that the FlankAttackModifier xml tag for promotions doesn't exist in the vanilla dll (it was only added in the expansion).

The only thing from Austria that can be directly ported is the UB.

How you would go about this is essentially the same as making a mod civ, i.e. create and entirely new Austria civ mod within the confines of the vanilla DLL and xml tags, copying what abilities you can, making up the rest, and just referencing the art of the expansion.

(And just to point out, almost every new ability and new promotion you see in the expansions was likely only added in the expansion to support the new civs or scenarios. Essentially, you'll have to recreate the functionality of every new trait and promotion tag from scratch, which might not be possible with vanilla's lua. Case in point, Carthage. There is no way to give a free building in every city (harbors) with the vanilla trait xml. Even if you use lua to manually place a harbor in every city, there is no way to set that building as free to not require any maintenance).