I really don't understand the need to have de jure kingdoms or Empires where none existed, especially in early start dates. We already have custom kingdom titles that allow for de jure drift, while tribes have powerful CBs while already allows the AI the ability to easily expand. De jure lands should be handled by start date in this way:
- CM start date: give southern Ruthenia and western Cumania to a de jure Khazaria; Rus, northern Ruthenia, and the Russian Empire should not exist
- Old gods: same as CM but, give Rurik the ability to create a titular Rus Kingdom via decision (like it was handled for Charlie), which insta de jure drifts any owned lands into the kingdom; give him and his offspring strong claims to the (current in-game) Ruthenian lands, which is western Khazaria in my setup; start Cumania with strong claims to eastern Khazaria
- 1066: western Rus and all of Ruthenia are all de jure Rus; call it Ruthenia if you're a Catholic; keep eastern Rus and any of those northeastern tribal lands without a de jure; the idea is that Pagans should still be able to more easily expand here via their invasion CB but, Orthodox Russians should have to fabricate claims since Russian expansion into this area didn't happen for another few hundred years