I know this is rather belated, but I've managed to pull it off... though it requires dynasties friendly harder contagious mode (and cheat mode is highly recommended). One way to do it with cheat mode is this:
Assuming all males for guests, choose Idris, Jake, Bradley, Ken, Laurence, and Paul as the first six victims in order. Assign yourself and Travis as the leaders of the two werewolf dynasties at the end; the order of everyone else does not matter for this setup.
Arrive first at the manor, and head to Idris's room to convert him (Travis will convert Jake at the same time). The werewolf kill after this would have been Idris, but you'll have already converted him, so he'll live.
After the first (lack of) kill, choose any room; it's not possible to spread the infection this night. The werewolf kill for this night would have been Jake, but Travis will have already converted him.
After the second "kill", go to the garden to convert Bradley and Ken. The next werewolf kill would have been Bradley, but you will have converted him just in time to keep him from getting killed.
After the third "kill", go to the cellar to convert Laurence and Milano. The next werewolf kill would have been Ken, but he will have already been converted the previous night.
After the fourth "kill", go to the kitchen to convert Marcus and Jerome. While you're there, Jake will convert Eddie at the balcony. The next werewolf kill would have been Laurence, but he should already have been converted from the previous night.
After the fifth "kill", go to the bedroom to convert Paul and Mikey. Laurence and Jake would have converted one another at the bar, but they both will have already been converted. The next werewolf kill would have been Paul, but he will have just been converted.
After the sixth "kill", you can go into any room, since Andrew (the last unconverted human) is set up to be converted by Idris; you can either go to the library to participate, join Travis and Eddie in the nursery for their romp, or go to any other room to skip having an adult scene. Regardless of which room you went to, you should then end up with the werewolf takeover ending, since everyone's now been converted.