Rans Enduro Sport, Hase Kettweisel Tandem, Merin Bear Valley beater bike
How lucky are you usually? There are a bunch of slightly different derailleur hangers. You're going to have to be pretty lucky to find exactly the one that you need. My advice is to buy two so you won't get into this position again.
You might be able to find a bolt-on hanger to bodge it with or maybe buy a Tourney derailleur that has the hanger attached.