not sure if you got anywhere with the buildings or not yet....

a. culture names are different between RTW and BI and probably where you want to use the lotus ones won't tie up anyway....

b. you need to amalgamate BI items with the revised RTW lotus ones - all of the .items files must end up in your mod-folder/data/items/ and referenced by the items.db file


there is off chance that the files you need may have same names and same lod levels as existed in the BI items.db - in which case you can just copy the lotus ones in...

more likely you might need to re-name some stuff which involves understanding and using this.
https://forums.totalwar.org/vb/showthread.php?t=60818
to regenerate the .db file - but not actually overwriting the .items - neither RTW or Blue Lotus actually supplies the .cas files so trying to generate new items won't work...
We did use modified Blue Lotus walls (with their permission) to some extent in EoDII which is BI mod, conversion is definitely possible, but not simple....