Surnames?

I was wondering if there was any way of getting rid of surnames like in RTW?

I'd like to know too- also how are those titles assigned like "the Mad" or "the Cunning." I'd like to mod those.

dont know

You can get rid of surnames by deleting them all from descr_names.txt

And those "titles" are called Epithet, they are tied to certain traits (search in export_descr_character_traits.txt for epithet)