Noob question about modding

Hi everyone. So I’ve decided to make myown mod, using AGE3. So, I want to give vietnamesse the southeaster architecture.

The questions is:can I copy all the architecture in one move, or do I have to change every building image oneby one?

I would gladly appreciate any advice/guide on the toppic.

Also, I want to give regional monks, probably ussing heroes unit. Would they keep the glow, or not?

Thanks for the advices

One by one in AGE3. But I think it may not be too difficult.