Personally, I assume following cultures:
Ulnarian Cultures (Sommerlund, Durenor)
Saxon influenced. Physically they resemble Scandinavian cultures, but there is little evidence of that in the names. There are also some celtic influences (Lachlan, Killean, Ronan) among some characters. Also, Durenese names tend to be fancier sounding (Ganon, Dorier, Madim, Viveka) reflecting the slightly more noble people, with possible french influences.
Male first names: Daron, Tym, Lorin, Aran, Jac, Lon, Oren, Tor, Vea, Baleon, Banedon, Ronan, Parsion, Ganon, Halvorc, Dorier, Madim, Lachlan, Killean, Remir, Paoll
Female first names: Thelda, Petrea, Vinas, Viveka, Madelon
Surnames: Faldon, Hobar, Rolny, Ladnor, Taynor, Calder, Galt, Medar, Kelman, Rhygar, Rendalim, Raker, Dryan
Vassa Cultures (Vassagonia, Anari, Shadaki etc)
Clearly middle eastern influences.
Male first names: Barraka, Maouk, Tipasa, Jhioua, Yranai, Khazullo, Rhous, Temujun, Dar-Isun
Female first names: Oriah, Jhani
Surnames: Moudalla, Dabudei, Guldarra. Surnames appear to be rare in Vassa lands. Often a family name is replaced by a nick name (as in Tipasa the Wanderer, Shasarak the Wytch-King)
To be continued...