The more I read the more I don’t know is this is for or or or . Probably all of that.

Just a quick observation:

Byzantium

First names
Andronicus – Latin and everything else is Greek. It should be Andronicos.
Dragos is Serbian name.
Imbert ???
John is English version of Ioannes.
There are both Constantine and Konstantinos.
Slavos ???
Volkanos is Latinized Serbian name Vukan and it should be Bolcanus. It seems that somebody read wrong translated version of “Alexiad” by Anna Comnena.

Surnames
Prvovencani – This is Serbian and means First-Crowned. They again included it from MTW.
Radomiros – Slavic name Radomir + os.

Hungary

Catastrophe! Somebody copy/paste Hungarian first names in surname category.

First names
Damjan is Serbian version of Damien.
Georgius and after that Gyorgy!
Kowacz is surname and wrong spelled.
Lukac is surname.
Peter and then Petri!

Surnames
Ambrus is first name (Ambrose).
Andras is first name (Andrew).
Bela is first name.
Ferenc is first name (Francis).
Geza is first name.
Gyorgy is first name (Georg).
Imre is first name (Emeric).
Istvan is first name (Stephen).
Jakab is first name (Jacob).
Janos is first name (John).
Jo ???
Karoly is first name (Karl).
Kazimierz is Polish first name.
Marton is first name (Martin).
Mate is Croatian first name.
Matyas is first name (Matthew).
Mihaly is first name (Michael).
Miklos is first name (Nicholas).
Otto is first name.
Pal is first name (Paul).
Samuel is first name.

Women
Adelaide – there is Australian town as name…

I can’t imagine situations in game with characters like Andras Andras, Miklos Miklos and similar.

List of names for the most factions are .