OK so I asked the mod developer the same question and this is his response.
Question:
Good day everyone.
I have more of a technical question
Is it possible to replace castle scenes interior/exterior from one mod to another? For example i quite like Tevarin castle and it's village from the Floris mod and would like to replace Tevarin castle from Bannerpage with it. Is it possible and if it is how would you proceed to do so?
Love the mod best one out there in many aspects thank you for the amazing work.
Cheers
Response:
yes
check parties.txt to get location numbers
then go to SceneObj folder, names are very intuitive, copy the scene you want and paste it over scene you are replacing
lastly check scenes.txt and make sure that you transfer terrain too for the scene you have copied in step above
Nadam se da je to ok.
LP
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Is it this simple?