Satan's skin is purple.
Since this mod takes place in the universe of the base game many years in the past, it's likely that Satan in this mod has a similar appearance to the Dearests. We just don't see it because of the artstyle. He might even be an ancestor to the Dearests.A Girlfriend that is related to the Dearests exists.
Considering the Girlfriend we see in the mod is not related to the Dearest family. It's likely that the present-day/demon Girlfriend also has a 30's counterpart too who serves as her great-great grandmother.