DEATH EATERS&VOLDEMORT
Right, so I needed to check on my canon details and timeline. My issue with introducing DE references was that it would distract from the initial purpose of the game: a fun, care-free roadtrip! Canon-wise, Voldemort started collecting followers pre-1970s. His first act of war came in 1970 when he began to recruit dark magical creatures. What I'm going to say game-wise is that there are whispers of Lord Voldemort and his followers, but the Ministry just dismisses it entirely. There's not been any attacks in the last 8 or so years as he's slowly been building connections/checking how strong his Horcruxes are. He does have the werewolves on side, though.
At this point in the game, none of the characters on the road-trip are Death Eaters. Regulus is in contact with Voldemort (and I don't mind adding Sev and Lucius to that mix, too).