DoA5 and its variants were released identically in Japan and western regions. Like, literally identically. If you put a Japanese copy in a US console, it would default to English subs, menus and even voices, and vice versa. The fact that DoA6 has English subs in Japan isn't really indicative of anything.
Free Step Dodge
Juihau
HHH816
i know DOA5 U.S version don't have marie rose in it's cover..let's hope DOA6 only come to that