Like I said, the Japanese element is largely out of the picture. Plus, the architecture has always been Arabic, it was the names/culture that were Japanese back in Daggerfall.
I also always thought of it as a change over time as the Redguards settled and adapted. It could also be an extension of the historic Crown vs. Forebear faction; the Crowns had more Japanese sounding names, while the Forebears had more "Imperialized" names. As for having names in Daggerfall, this list has rather un-Japanese sounding names from both Daggerfall and Redguard.
http://www.uesp.net/wiki/Lore:Redguard_Names#Daggerfall
Culture is definitely bang on though.