I know this is probably redundant to talk about since not many people really care about minor details to characters, but while looking through DOAWK through different languages I saw the Japanese version and I've noticed that they've added another finger on the characters in the Japanese version giving the characters 5 fingered hands.
I think they changed the characters fingers so Japanese readers wouldn't view the characters as apart of some mafia. I know they've done this similar thing with Bob the Builder, Abe from Oddworld (Gave him 3 fingers), Fat Princess, and The Simpsons (on VHS and Videogame covers) when they were marketing them in Japan.
As I said below, I think they changed it from 4 and 5 because in Japan, Yakuza members would always chop off fingers if they are unable to pay back a debt, or as punishment for other offences that don't warrant death, and 4 means death in Japanese superstition.
I guess since the series was aimed at children in Japan and they didn't want kids to think the characters would be related to the Yakuza. I maybe wrong about this but these are basically my theories.